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Exponential Smoothing in Excel (Find α) | Use Solver to find smoothing constant alpha

Joshua Emmanuel · YouTube · 4:48

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Reviewed learning material · Video analysis · English
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This 120-second Excel tutorial segment introduces simple exponential smoothing on a seven-month demand series with α=0.4α=0.4. It explains the initialization rule when no first-period forecast is supplied, enters the recurrence Ft=αAt−1+(1−α)Ft−1F_t = αA_{t-1} + (1-α)F_{t-1} in Excel using absolute references, copies the forecast formula down the column, and then computes the absolute-error and squared-error columns. The APE, MAD, MSE, and MAPE labels are visible, but their calculations are not demonstrated within this clip. This 120-second Excel tutorial segment shows how to compute forecast-error metrics for exponential smoothing and then use Solver to choose the smoothing constant alpha that minimizes MAD. It first defines APE as |Error| divided by actual Demand times 100, fills the APE column, and computes MAD, MSE, and MAPE as column averages. The narrator explicitly notes that the alpha minimizing MAD may differ from the alpha minimizing MSE. The second half builds a Solver model with objective cell EE12 (MAD), changing cell CC2 (alpha), constraints 0 <= alpha <= 1, and GRG Nonlinear method. After solving, the worksheet updates to alpha = 0.30841, 1-alpha = 0.69159, MAD = 4.47553, MSE = 29.84198, and MAPE = 10.88013, with Solver reporting that all constraints are satisfied. This 48-second Excel demonstration shows how to choose the exponential smoothing constant α\alpha by minimizing forecast error metrics with Solver. It begins from a completed MAD optimization result with α≈0.3084\alpha \approx 0.3084, then changes the Solver objective to MSE (cell F12) and obtains α≈0.3144\alpha \approx 0.3144. Finally it repeats the process for MAPE (cell G12), returning α≈0.3084\alpha \approx 0.3084, which the narrator notes matches the MAD case. The visible Solver setup keeps C3C3 as the changing variable cell, imposes C3≤1C3 \le 1, enables nonnegativity, and uses the GRG Nonlinear method.

Use the learning inspector for key ideas and moments, or open the reading tabs for the complete notes.

Chapters

0:00Worksheet setup and goal0:25Initialization rule for missing first forecast0:49Entering the exponential smoothing formula1:31Copying forecasts down the table1:39Computing absolute and squared errors2:00Compute APE from absolute error and demand2:17Calculate MAD, MSE, and MAPE by averaging columns2:30Note that MAD and MSE can imply different optimal alpha2:42Open Excel Solver from the Data tab2:52Set Solver objective to minimize MAD by changing alpha3:13Add the constraint 0 <= alpha <= 13:52Run GRG Nonlinear Solve and read the optimal alpha4:00MAD-optimal alpha already found4:13Switch Solver objective to MSE4:25MSE solution: alpha = 0.31444:34Switch Solver objective to MAPE4:38MAPE solution matches MAD4:43Closing summary

Learning script

Generated from the video's visuals and explanation; not verbatim speech.

The clip opens on an Excel sheet prepared for exponential smoothing. At the top, the parameter cells show α=0.4α=0.4 and 1−α=0.61-α=0.6. Below them is a seven-month demand table with columns Month, Demand, Forecast, |Error|, Error², and APE, plus summary labels MAD, MSE, and MAPE underneath. The narrator states the goal: build exponential smoothing forecasts in Excel and later use Solver to find the best α.

Before any recursion can start, the video addresses the missing initial forecast. The rule given is that if no forecast is supplied for period 1, then use the first actual value as the starting forecast. On screen, blue overlays summarize this as F1=A1F1 = A1 and F2=A1F2 = A1. In the worksheet, the period-2 forecast cell is filled directly from the period-1 demand, so F2 becomes 48.

With the seed established, the first true exponential-smoothing calculation occurs in period 3. The displayed formula is Forecast = α × Actual (in the last period) + (1-α) × Forecast (in the last period). In Excel notation this becomes =CC2∗C62*C6+DD2∗D62*D6. The dollar signs are emphasized because they lock the parameter cells while the row-specific demand and forecast references move downward.

Substituting the visible values gives F3=0.4×44+0.6×48=46.4F3 = 0.4\times 44 + 0.6\times 48 = 46.4. After that single formula is entered, the fill handle is dragged down through period 7. The copied recurrence produces the remaining forecasts 43.84, 46.304, 42.5824, and 42.34944, showing how one recursive equation generates the entire forecast path once initialized.

The tutorial then turns to error diagnostics. In the |Error| column, the formula =ABS(C6-D6) computes the magnitude of each forecast deviation from actual demand. Filling that formula downward yields 4, 6.4, 6.16, 9.304, 0.5824, and 0.65056 for periods 2 through 7.

Next, the Error² column is created by squaring the absolute errors with =E62E6^2. The resulting displayed values are 16, 40.96, 37.9456, 86.56442, 0.33919, and 0.423228. The APE column and the summary labels MAD, MSE, and MAPE are present in the layout, but their computations are not reached within this excerpt.

The segment begins with the spreadsheet already populated by demand, forecast, |Error|, and Error^2 columns. The immediate task is to create the APE column. The narrator states the rule directly: divide the absolute error by the actual value and multiply by 100. On screen, cell G6 receives =E6/C6∗100E6/C6*100, making clear that the denominator is the demand cell C6 rather than the forecast cell D6.

Once the first APE entry is correct, the formula is copied down the rest of the table. The visible results become 9.090909, 16, 12.32, 25.14595, 1.386667, and 1.51293. This completes the rowwise percentage-error calculation needed before any aggregate MAPE can be formed.

The next task is to summarize the errors in one row. The narrator says to find MAD by using equals average to take the mean of the absolute errors. Cell E12 is filled with =AVERAGE(E6:E11), and the displayed MAD is 4.51616. Mathematically, this is just the arithmetic mean of the |Error| column over the six listed periods.

Instead of retyping new formulas, the presenter drags the same averaging formula across to the neighboring columns. This produces MSE = 30.37207 from the Error^2 column and MAPE = 10.90941 from the APE column. The key structural point is that MAD, MSE, and MAPE are all column averages of their respective error measures.

Before optimizing, the narration adds an important conceptual caution: the best alpha for minimizing MAD may not be the same as the best alpha for minimizing MSE. This signals that the choice of loss function matters; different error criteria weight forecast mistakes differently and therefore can select different smoothing constants.

The workflow then shifts from calculation to optimization. The user opens the Data tab and launches Solver. This is the tool that will search over alpha values rather than merely evaluating one fixed choice such as alpha = 0.4.

Inside Solver Parameters, the model is specified step by step. The Set Objective field is pointed to EE12, the MAD cell, and the direction is set to Min. The By Changing Variable Cells field is set to CC2, the alpha cell. In mathematical terms, the program is being asked to solve min MAD(alpha) with alpha as the decision variable.

The feasible region for alpha is then enforced. The narrator explains that alpha must lie between 0 and 1. The checkbox Make Unconstrained Variables Non-Negative is left checked to impose alpha >= 0, and an explicit constraint CC2 <= 1 is added to impose alpha <= 1. Together these encode the standard smoothing-constant restriction 0 <= alpha <= 1.

Finally, the solving method is left as GRG Nonlinear and Solve is clicked. The Solver Results dialog reports convergence and satisfaction of all constraints. The worksheet updates to alpha = 0.30841 and 1-alpha = 0.69159, and the summary row changes to MAD = 4.47553, MSE = 29.84198, and MAPE = 10.88013. Thus the optimized alpha lowers MAD from 4.51616 to 4.47553 relative to the initial alpha = 0.4 case.

The clip opens on an Excel worksheet already showing a Solver result for exponential smoothing. Cell C3 contains α=0.30841\alpha=0.30841, cell D3 contains 1−α=0.691591-\alpha=0.69159, and the summary row shows MAD = 4.47553, MSE = 29.84198, and MAPE = 10.88013. The narrator states that this is the optimal alpha for obtaining the smallest MAD.

The worksheet is then reset to a trial value α=0.4\alpha=0.4, giving MAD = 4.51616, MSE = 30.37207, and MAPE = 10.90941. The next task announced in the audio is to determine the best alpha that minimizes MSE.

The Solver Parameters dialog is opened. The objective cell is set to FF12, the MSE cell, with To: Min. The changing variable cell remains CC3, the constraint list shows CC3 <= 1, Make Unconstrained Variables Non-Negative is checked, and the solving method is GRG Nonlinear. This shows that the same model structure is reused and only the objective is changed.

After Solve is clicked, Solver reports that a solution has been found and that all constraints and optimality conditions are satisfied. The worksheet updates to α=0.3144\alpha=0.3144, 1−α=0.68561-\alpha=0.6856, and MSE = 29.83905. The narrator identifies 0.3144 as the best alpha for minimizing MSE.

The process is repeated for MAPE. Solver Parameters now sets the objective to GG12 while keeping the same changing cell CC3, the same constraint CC3 <= 1, and the same GRG Nonlinear method.

The resulting Solver output returns α=0.30841\alpha=0.30841. The narrator explicitly says this is the same as with MAD. The closing line summarizes the lesson: this is how to use Solver to find the best alpha for exponential smoothing.

Knowledge cards

01

Exponential smoothing setup in Excel

The worksheet stores the smoothing parameters separately from the data table: α is in C2 with value 0.4, and 1-α is in D2 with value 0.6. The demand series has seven monthly observations, and the table reserves columns for Forecast, |Error|, Error², and APE, with summary labels MAD, MSE, and MAPE below.

02

Initialization when no first forecast is given

If the problem does not provide an initial forecast, the video uses the first actual observation as the seed. This is summarized on screen by F1=A1F1 = A1 and F2=A1F2 = A1, so the period-2 forecast is set equal to the period-1 demand before the recurrence starts at period 3.

F1=A1,F2=A1F_1=A_1,\quad F_2=A_1
03

Simple exponential smoothing recurrence

Each new forecast is a weighted average of the latest actual value and the latest forecast. In the worksheet this is implemented as =CC2∗C62*C6+DD2∗D62*D6, corresponding to Ft=αAt−1+(1−α)Ft−1F_t = αA_{t-1} + (1-α)F_{t-1}. With α=0.4α=0.4, the period-3 forecast is 0.4×44+0.6×48=46.40.4\times 44 + 0.6\times 48 = 46.4.

Ft=αAt−1+(1−α)Ft−1F_t = \alpha A_{t-1} + (1-\alpha)F_{t-1}
04

Why absolute references matter when copying formulas

The parameter cells are written as CC2 and DD2 so they remain fixed when the formula is copied downward. Without locking them, later rows would reference the wrong cells instead of always using the same α and 1-α values.

05

Forecast results for the seven-month example

After initialization and recursion, the displayed forecasts for periods 2 through 7 are 48, 46.4, 43.84, 46.304, 42.5824, and 42.34944. These come from repeatedly applying the same exponential smoothing update to the demand series 48, 44, 40, 50, 37, 42, 43.

06

Absolute error column

The |Error| column measures how far each forecast is from the actual demand without regard to sign. In Excel the formula is =ABS(C6-D6), giving 4, 6.4, 6.16, 9.304, 0.5824, and 0.65056 for periods 2 through 7.

∣et∣=∣At−Ft∣|e_t| = |A_t - F_t|
07

Squared error column

The Error² column is obtained by squaring the absolute errors with =E62E6^2. The displayed values are 16, 40.96, 37.9456, 86.56442, 0.33919, and 0.423228. This prepares the rowwise inputs needed for later summary measures such as MSE, although those summaries are not computed in this clip.

et2=(∣et∣)2e_t^2 = (|e_t|)^2
08

Absolute Percentage Error (APE)

APE for a period is defined in the video as the absolute forecast error divided by the actual demand, then multiplied by 100. The spreadsheet implements this as =E6/C6∗100E6/C6*100 and copies the formula down the APE column.

APE=∣Error∣Demand×100\text{APE}=\frac{|\text{Error}|}{\text{Demand}}\times 100
09

MAD as the average of absolute errors

MAD is computed by averaging the |Error| column. The visible formula is =AVERAGE(E6:E11), giving MAD = 4.51616 for the initial alpha = 0.4 worksheet.

MAD=1n∑i=1n∣Errori∣\text{MAD}=\frac{1}{n}\sum_{i=1}^{n}|\text{Error}_i|
10

MSE and MAPE from the same averaging pattern

After MAD is calculated, the same average formula is dragged across to the Error^2 and APE columns. This yields MSE = 30.37207 and MAPE = 10.90941 in the initial state.

MSE=1n∑Error2,MAPE=1n∑APE\text{MSE}=\frac{1}{n}\sum \text{Error}^2,\quad \text{MAPE}=\frac{1}{n}\sum \text{APE}
11

MAD and MSE can select different alpha values

The narrator explicitly warns that the alpha minimizing MAD may differ from the alpha minimizing MSE. This is a conceptual caution about choosing the optimization criterion before running Solver.

12

Solver setup to minimize MAD over alpha

The optimization model sets the objective cell to EE12 (MAD), chooses Min, and designates CC2 (alpha) as the changing variable cell. This turns the spreadsheet into the mathematical problem min MAD(alpha).

min⁡α MAD(α)\min_{\alpha}\ \text{MAD}(\alpha)
13

Feasible range for the smoothing constant

The video constrains alpha to the interval from 0 to 1. Non-negativity is kept on through the Solver option, and the upper bound is added explicitly as CC2 <= 1.

0≤α≤10 \le \alpha \le 1
14

Optimal Solver result for this worksheet

Using GRG Nonlinear, Solver converges to alpha = 0.30841 with all constraints satisfied. The updated summary values are MAD = 4.47553, MSE = 29.84198, and MAPE = 10.88013.

α∗=0.30841, MAD∗=4.47553\alpha^*=0.30841,\ \text{MAD}^*=4.47553
15

Exponential smoothing alpha in Excel

In this example, the smoothing constant α\alpha is stored in cell C3 and its complement 1−α1-\alpha in D3. Changing α\alpha updates the forecast column and all downstream error measures, so α\alpha is the quantity being optimized.

16

Error metrics used to judge alpha

The worksheet computes |Error|, Error², and APE row by row, then aggregates them into MAD in E12, MSE in F12, and MAPE in G12. These three summary cells are the candidate objectives for Solver.

MAD=1n∑∣ei∣,MSE=1n∑ei2,MAPE=1n∑∣eiyi∣×100\text{MAD}=\frac{1}{n}\sum |e_i|,\quad \text{MSE}=\frac{1}{n}\sum e_i^2,\quad \text{MAPE}=\frac{1}{n}\sum \left|\frac{e_i}{y_i}\right|\times 100
17

MAD-optimal result shown at the start

The opening Solver result indicates that minimizing MAD for this dataset gives α≈0.3084\alpha \approx 0.3084, with MAD = 4.47553. The narrator directly states that this alpha yields the smallest MAD possible.

α≈0.3084,MAD=4.47553\alpha \approx 0.3084,\quad \text{MAD}=4.47553
18

How to switch Solver from MAD to MSE

To optimize MSE instead of MAD, the Solver objective cell is changed to FF12 while leaving the rest of the setup intact: changing cell CC3, constraint C3≤1C3 \le 1, nonnegativity enabled, and GRG Nonlinear selected.

Objective: F12,  Min,  Changing cell: C3,  C3≤1\text{Objective: } F12,\; \text{Min},\; \text{Changing cell: } C3,\; C3 \le 1
19

MSE-optimal result

Running Solver with MSE as the objective produces α=0.3144\alpha = 0.3144 and MSE = 29.83905. This is slightly different from the MAD optimum, illustrating that the chosen error metric affects the best smoothing constant.

α=0.3144,MSE=29.83905\alpha = 0.3144,\quad \text{MSE}=29.83905
20

MAPE-optimal result

When the objective is changed to GG12 (MAPE), Solver returns α≈0.3084\alpha \approx 0.3084, which the narrator notes is the same as for MAD in this example.

α≈0.3084\alpha \approx 0.3084
21

Key takeaway from the clip

The video's overall lesson is that Excel Solver can be used to find the best exponential smoothing constant by minimizing a chosen forecast error criterion such as MAD, MSE, or MAPE.

Detailed learning notes

Explore conditions, steps and evidence. Supplementary explanations are labeled separately from content shown in the video.

Symbols · 30

α\alpha

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Cell C1 is labeled α and cell C2 contains 0.4.

  2. Audio
    Observation

    The narrator says he has chosen a random value for alpha, which is 0.4 here.

Symbol

α\alpha

Meaning

Smoothing constant used in the exponential smoothing forecast formula.

Domain

In this clip it is set to 0.4; the video does not state the general admissible range.

1−α1-\alpha

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Cell D1 is labeled 1 - α and cell D2 contains 0.6.

  2. Formula
    Observation

    The displayed forecast formula uses the term (1-α).

Symbol

1−α1-\alpha

Meaning

Complement of the smoothing constant, multiplying the previous forecast in the exponential smoothing update.

Domain

Here it equals 0.6 because α=0.4α=0.4.

Demand\text{Demand}

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Column C is headed Demand and lists 48, 44, 40, 50, 37, 42, 43 for months 1 through 7.

  2. Audio
    Observation

    The narrator refers to these as time series data and later as actual values.

Symbol

Demand\text{Demand}

Meaning

Actual observed time-series value for each month.

Domain

Seven monthly observations are shown in the worksheet.

Forecast\text{Forecast}

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Column D is headed Forecast.

  2. Audio
    Observation

    The narrator explains how to compute forecasts for periods 2 through 7.

Symbol

Forecast\text{Forecast}

Meaning

Exponentially smoothed forecast value for a period.

Domain

In this clip, forecasts are filled from period 2 onward.

|Error\text{Error}|

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Column E is headed |Error|.

  2. Formula
    Observation

    The entered formula is =ABS(C6-D6).

Symbol

|Error\text{Error}|

Meaning

Absolute forecast error, the magnitude of the difference between actual demand and forecast.

Domain

Computed for periods with both demand and forecast values.

Error2\text{Error}^2

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Column F is headed Error².

  2. Formula
    Observation

    The entered formula is =E62E6^2.

Symbol

Error2\text{Error}^2

Meaning

Squared forecast error, obtained by squaring the absolute error column.

Domain

Computed rowwise after |Error| is available.

APE\text{APE}

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Column G is headed APE.

  2. Audio
    Observation

    The narrator says he will calculate absolute percent errors.

Uncertainties
  1. No APE formula or numeric APE values are shown within this 120-second clip.

Symbol

APE\text{APE}

Meaning

Absolute percent error column introduced in the worksheet layout.

Domain

Header is visible, but calculation is not demonstrated before the clip ends.

MAD\text{MAD}

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Summary labels MAD, MSE, and MAPE appear below the table.

  2. Audio
    Observation

    The narrator mentions calculating absolute errors, squared errors, and absolute percent errors.

Uncertainties
  1. The clip shows only the labels; no formulas or values for MAD are entered before 120 seconds.

Symbol

MAD\text{MAD}

Meaning

Mean absolute deviation summary metric label in the worksheet.

Domain

Label only in this clip.

MSE\text{MSE}

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Summary labels MAD, MSE, and MAPE appear below the table.

Uncertainties
  1. The clip shows only the label; no formula or value for MSE is entered before 120 seconds.

Symbol

MSE\text{MSE}

Meaning

Mean squared error summary metric label in the worksheet.

Domain

Label only in this clip.

MAPE\text{MAPE}

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Summary labels MAD, MSE, and MAPE appear below the table.

Uncertainties
  1. The clip shows only the label; no formula or value for MAPE is entered before 120 seconds.

Symbol

MAPE\text{MAPE}

Meaning

Mean absolute percentage error summary metric label in the worksheet.

Domain

Label only in this clip.

α\alpha

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Cell C1 is labeled α and cell C2 contains 0.4.

  2. Audio
    Observation

    The narration says the variable value we want to change is alpha and that alpha needs to be between 0 and 1.

Symbol

α\alpha

Meaning

Smoothing constant used as the decision variable in the exponential-smoothing worksheet.

Domain

Constrained to 0≤α≤10 \le \alpha \le 1 in the Solver setup.

1−α1-\alpha

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Cell D1 is labeled 1−α1 - \alpha and cell D2 contains 0.6.

Symbol

1−α1-\alpha

Meaning

Complement of the smoothing constant shown beside α\alpha in the worksheet header.

Knowledge points · 13

One-step exponential smoothing forecast formula

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator states: alpha times actual in the last period plus one minus alpha times forecast in the last period.

  2. Diagram
    Observation

    On-screen text reads: Forecast = α × Actual (in the last period) + (1-α) × Forecast (in the last period).

  3. Formula
    Observation

    Excel formula entered in D7 is =CC2∗C62*C6+DD2∗D62*D6.

Formula
Explanation

The clip presents the standard simple exponential smoothing update: the next forecast is a weighted average of the most recent actual observation and the most recent forecast. In the worksheet, the weights are stored in fixed cells so the same formula can be copied downward.

Formula
Ft=αAt−1+(1−α)Ft−1F_t = \alpha A_{t-1} + (1-\alpha)F_{t-1}
Conditions
  1. Uses the immediately preceding actual value and preceding forecast value.

  2. In this example α is taken from cell C2 and 1-α from cell D2.

Prerequisites
  1. Initialization rule when no prior forecast is supplied
  2. Using absolute references for parameters in Excel

Initialization rule when no prior forecast is supplied

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator says that if you are not given a forecast for the first period, then the forecast is the actual value for the first period, and consequently it will be the forecast for the second period as well.

  2. Diagram
    Observation

    Blue overlays show F1=A1F1 = A1 and F2=A1F2 = A1.

  3. Formula
    Observation

    Cell D6 is filled with =C5, giving forecast 48 for period 2.

Method
Explanation

Because no earlier forecast is provided for period 1, the video sets the starting forecast equal to the first actual demand. The same value is then carried into period 2, so the first recursive forecast calculation begins at period 3.

Formula
F1=A1,F2=A1F_1=A_1,\quad F_2=A_1
Conditions
  1. Applies when the problem does not provide an exogenous initial forecast.

  2. Demonstrated on a seven-period monthly demand series.

Using absolute references for parameters in Excel

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator says to press F4 to make it absolute and explains that the dollar signs ensure the alpha cell is locked down when copying the formula to other cells.

  2. Formula
    Observation

    Formula bar shows =CC2∗C62*C6+DD2∗D62*D6.

  3. Diagram
    Observation

    An on-screen key overlay shows F4 while the reference is edited.

Method
Explanation

The parameter cells for α and 1-α are written with dollar signs so they remain fixed when the forecast formula is copied to lower rows. By contrast, the demand and forecast references are relative so they shift row by row.

Conditions
  1. Needed when a formula will be copied across multiple rows or columns.

  2. Used here to keep the smoothing constants fixed while updating period-specific inputs.

Absolute forecast error in Excel

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator says: For the absolute errors we type equals ABS and then actual minus forecast value.

  2. Formula
    Observation

    Cell E6 contains =ABS(C6-D6).

  3. Diagram
    Observation

    Column E is headed |Error| and fills downward with 4, 6.4, 6.16, 9.304, 0.5824, 0.65056.

Formula
Explanation

The worksheet computes the magnitude of each period’s forecast error by subtracting the forecast from the actual demand and applying ABS. This produces a nonnegative error measure for each row.

Formula
∣et∣=∣At−Ft∣|e_t| = |A_t - F_t|
Conditions
  1. Requires both an actual value and a forecast value in the same row.

Prerequisites
  1. Initialization rule when no prior forecast is supplied
  2. One-step exponential smoothing forecast formula

Squared forecast error from the absolute error column

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator says: For the squared error, square the absolute error and double click the handle to copy it down.

  2. Formula
    Observation

    Cell F6 contains =E62E6^2.

  3. Diagram
    Observation

    Column F is headed Error² and fills with 16, 40.96, 37.9456, 86.56442, 0.33919, 0.423228.

Uncertainties
  1. The final copied values are visible only near the end of the clip; the last row fill completes right at the boundary.

Formula
Explanation

After the absolute errors are computed, the video squares those values to create the Error² column. Because squaring removes sign, using the absolute error or the raw error gives the same squared result.

Formula
et2=(∣et∣)2=(At−Ft)2e_t^2 = (|e_t|)^2 = (A_t-F_t)^2
Conditions
  1. The |Error| column must already be populated.

Prerequisites
  1. Absolute forecast error in Excel

Absolute Percentage Error (APE)

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    For absolute percent error, divide the absolute error by the actual value and multiply by 100.

  2. Formula
    Observation

    Cell G6 is filled with =E6/C6∗100E6/C6*100.

  3. Animation
    Observation

    The formula is entered in G6 and then copied down through the APE column.

Formula
Explanation

The video defines APE for each month as the absolute forecast error divided by the actual demand, then multiplied by 100. In the worksheet this is implemented as =E6/C6∗100E6/C6*100 and copied downward, producing percentage values such as 9.090909 for month 2.

Formula
APE=∣Error∣Demand×100\text{APE}=\frac{|\text{Error}|}{\text{Demand}}\times 100
Conditions
  1. Use the absolute error, not the signed error.

  2. Divide by the actual demand value for the same period.

  3. Multiply by 100 to express the result as a percentage.

Prerequisites
  1. |Error\text{Error}|
  2. Demand\text{Demand}
  3. APE\text{APE}

Mean Absolute Deviation (MAD)

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    To find MAD, we use equals average to find the mean of the absolute errors.

  2. Formula
    Observation

    Cell E12 is filled with =AVERAGE(E6:E11).

  3. Diagram
    Observation

    The resulting MAD value shown is 4.51616.

Definition
Explanation

MAD is presented as the mean of the absolute errors. The spreadsheet computes it with =AVERAGE(E6:E11), averaging the |Error| column over months 2 through 7.

Formula
MAD=1n∑i=1n∣Errori∣\text{MAD}=\frac{1}{n}\sum_{i=1}^{n}|\text{Error}_i|
Conditions
  1. Average the absolute errors over the chosen set of periods.

  2. In this clip the averaged range is E6:E11.

Prerequisites
  1. |Error\text{Error}|
  2. MAD\text{MAD}

Computing MSE and MAPE by extending the average formula

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    Then drag to copy the formula for MSE and MAPE.

  2. Animation
    Observation

    The average formula from E12 is dragged across to F12 and G12.

  3. Diagram
    Observation

    F12 becomes 30.37207 and G12 becomes 10.90941.

Method
Explanation

After MAD is computed as an average of |Error|, the same averaging method is copied horizontally to the Error^2 and APE columns. This yields MSE as the average of squared errors and MAPE as the average of absolute percentage errors.

Formula
MSE=1n∑i=1nErrori2,MAPE=1n∑i=1nAPEi\text{MSE}=\frac{1}{n}\sum_{i=1}^{n}\text{Error}_i^2,\quad \text{MAPE}=\frac{1}{n}\sum_{i=1}^{n}\text{APE}_i
Conditions
  1. The copied formula must reference the corresponding column range.

  2. In this worksheet the displayed results are MSE = 30.37207 and MAPE = 10.90941.

Prerequisites
  1. Mean Absolute Deviation (MAD)
  2. Error2\text{Error}^2
  3. APE\text{APE}
  4. MSE\text{MSE}
  5. MAPE\text{MAPE}

Solver setup for minimizing MAD with respect to alpha

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    Now suppose we want the best alpha that minimizes MAD. For set objective, we click on the MAD value. Click Min for minimization. The variable value we want to change is alpha, so we click the alpha value for the changing variable cells.

  2. Diagram
    Observation

    Solver Parameters shows Set Objective: EE12, To: Min, By Changing Variable Cells: CC2.

Method
Explanation

The video configures Excel Solver to choose the smoothing constant alpha that gives the smallest MAD. The objective cell is the MAD cell E12, the direction is Min, and the changing cell is the alpha cell C2.

Formula
min⁡α MAD(α)\min_{\alpha}\ \text{MAD}(\alpha)
Conditions
  1. Objective cell is EE12 (MAD).

  2. Changing variable cell is CC2(α)2 (\alpha).

  3. Optimization direction is Min.

Prerequisites
  1. Mean Absolute Deviation (MAD)
  2. α\alpha
  3. MAD\text{MAD}

Constraint 0≤α≤10 \le \alpha \le 1 in Solver

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    Now, alpha needs to be between zero and one. This checked box here says make unconstrained variable non-negative. That is, we'll leave this box checked if we want alpha to be greater than or equal to zero. To ensure alpha is less than or equal to one, we click Add here to add the constraint. For cell reference, we select the alpha value. Make sure the less than or equal sign is selected, then input one on the right here. Click OK.

  2. Diagram
    Observation

    Solver Parameters shows Make Unconstrained Variables Non-Negative checked and Subject to the Constraints: CC2 <= 1.

  3. Animation
    Observation

    An overlay displays 0≤α≤10 \leq \alpha \leq 1 while the constraint is being explained.

Definition
Explanation

The smoothing constant is restricted to the interval from 0 to 1. The lower bound is enforced by leaving Make Unconstrained Variables Non-Negative checked, and the upper bound is added explicitly as CC2 <= 1.

Formula
0≤α≤10 \le \alpha \le 1
Conditions
  1. Keep Make Unconstrained Variables Non-Negative checked for α≥0\alpha \ge 0.

  2. Add the explicit constraint CC2 <= 1 for α≤1\alpha \le 1.

Prerequisites
  1. α\alpha
  2. Solver setup for minimizing MAD with respect to alpha

Exponential smoothing parameter selection context

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator concludes: 'And that's how to use Solver to find the best alpha for exponential smoothing.'

  2. Formula
    Observation

    The worksheet contains α, 1 - α, Demand, Forecast, |Error|, Error², APE, MAD, MSE, and MAPE.

Uncertainties
  1. The explicit recurrence formula for exponential smoothing is not shown in this clip.

Definition
Explanation

This clip demonstrates choosing the smoothing constant α\alpha in an exponential smoothing model by minimizing forecast error measures computed in Excel. The spreadsheet stores α\alpha in cell C3 and its complement 1−α1-\alpha in D3, then updates forecasts and error summaries whenever α\alpha changes.

Formula
Conditions
  1. The model is being tuned on a fixed historical demand series.

  2. α\alpha is treated as the optimization variable.

  3. Error metrics are recomputed automatically from the current α\alpha.

Forecast error metrics used for tuning alpha

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Columns E, F, and G are labeled |Error|, Error², and APE; row 12 labels the averages as MAD, MSE, and MAPE.

  2. Audio
    Observation

    The narrator explicitly names MAD, MSE, and MAPE as the criteria being minimized.

Definition
Explanation

The video uses three aggregate error measures to evaluate a chosen α\alpha: MAD from the absolute errors, MSE from the squared errors, and MAPE from the absolute percentage errors. These are displayed as single summary cells E12, F12, and G12.

Formula
MAD=1n∑i=1n∣ei∣,MSE=1n∑i=1nei2,MAPE=1n∑i=1n∣eiyi∣×100\text{MAD}=\frac{1}{n}\sum_{i=1}^{n}|e_i|,\quad \text{MSE}=\frac{1}{n}\sum_{i=1}^{n}e_i^2,\quad \text{MAPE}=\frac{1}{n}\sum_{i=1}^{n}\left|\frac{e_i}{y_i}\right|\times 100
Conditions
  1. eie_i denotes forecast error for period ii.

  2. yiy_i denotes actual demand for period ii.

  3. The formulas shown here are the standard interpretations consistent with the displayed columns; the clip itself only shows the column headings and summary labels.

Prerequisites
  1. Exponential smoothing parameter selection context
Claims and conditions · 6

Initialization claim used in this example

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator explicitly states the rule for exponential smoothing when no first-period forecast is given.

  2. Diagram
    Observation

    Overlays F1=A1F1 = A1 and F2=A1F2 = A1 visually restate the same rule.

Proposition
Statement

If no forecast is given for the first period, then the first-period forecast is taken to be the first actual value, and that same value is also used as the forecast for the second period.

Hypotheses
  1. The method being applied is exponential smoothing.

  2. No external initial forecast is supplied for period 1.

Quantifiers

For the demonstrated time series in this worksheet.

Different error measures can imply different optimal alpha values

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    Note that the best alpha that will minimize MAD may differ from the one that will minimize MSE.

Proposition
Statement

The value of α\alpha that minimizes MAD need not be the same as the value of α\alpha that minimizes MSE.

Hypotheses
  1. The forecasts depend on α\alpha.

  2. MAD and MSE are both being used as optimization criteria.

Quantifiers

There exist cases in which the minimizer of MAD differs from the minimizer of MSE.

Solver returns a feasible minimizing alpha for MAD

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Solver Results states: Solver has converged to the current solution. All Constraints are satisfied.

  2. Diagram
    Observation

    After solving, C2 changes from 0.4 to 0.30841 and D2 changes from 0.6 to 0.69159.

  3. Diagram
    Observation

    The updated summary row shows MAD = 4.47553, MSE = 29.84198, MAPE = 10.88013.

Proposition
Statement

Using the configured Solver model, the reported solution is α=0.30841\alpha = 0.30841 with MAD = 4.47553, and all constraints are satisfied.

Hypotheses
  1. Set Objective is EE12.

  2. To is Min.

  3. By Changing Variable Cells is CC2.

  4. Make Unconstrained Variables Non-Negative is checked.

  5. Constraint CC2 <= 1 is imposed.

  6. Solving Method is GRG Nonlinear.

Quantifiers

For the displayed worksheet and Solver settings, the returned solution satisfies the stated constraints.

Optimal alpha for minimizing MAD

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator says: 'You can see here that the optimal alpha value is point three zero eight four. That is, to obtain the smallest MAD possible, we should set alpha to about point three zero eight four.'

  2. Formula
    Observation

    Solver Results is open with α=0.30841α=0.30841 in C3 and MAD=4.47553 in E12.

Proposition
Statement

For the displayed dataset and spreadsheet setup, the Solver result identifies α≈0.3084\alpha \approx 0.3084 as the value that minimizes MAD.

Hypotheses
  1. The demand series and forecast-error calculations are those shown in the worksheet.

  2. Solver is minimizing cell E12 (MAD).

  3. The changing cell is C3 (α\alpha).

  4. The constraint C3≤1C3 \le 1 is in force.

Quantifiers

For the specific worksheet example shown in the clip.

Optimal alpha for minimizing MSE

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator says: 'Now let's determine the best alpha that will minimize MSE... And we can see here that the best alpha that minimizes MSE is point three one four four.'

  2. Formula
    Observation

    Solver Parameters shows objective FF12, Min, changing cell CC3, constraint CC3 <= 1; after Solve, C3=0.3144C3=0.3144 and F12=29.83905F12=29.83905.

Proposition
Statement

For the same worksheet example, changing the Solver objective to MSE yields an optimal smoothing constant α≈0.3144\alpha \approx 0.3144.

Hypotheses
  1. Solver objective cell is F12 (MSE).

  2. Changing variable cell remains C3 (α\alpha).

  3. Constraint C3≤1C3 \le 1 remains active.

  4. GRG Nonlinear method is used.

Quantifiers

For the specific worksheet example shown in the clip.

Optimal alpha for minimizing MAPE

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator says: 'Doing the same for MAPE, we obtain point three zero eight four, just like with MAD.'

  2. Formula
    Observation

    Solver Parameters shows objective GG12, Min, changing cell CC3, constraint CC3 <= 1; Solver Results then shows C3=0.30841C3=0.30841.

Uncertainties
  1. The final MAPE value after the MAPE run is not clearly emphasized in audio, though the worksheet shows 10.88013 in G12.

Proposition
Statement

For the same worksheet example, minimizing MAPE gives α≈0.3084\alpha \approx 0.3084, matching the MAD result reported by the narrator.

Hypotheses
  1. Solver objective cell is G12 (MAPE).

  2. Changing variable cell remains C3 (α\alpha).

  3. Constraint C3≤1C3 \le 1 remains active.

  4. GRG Nonlinear method is used.

Quantifiers

For the specific worksheet example shown in the clip.

Derivations and proofs · 7

Derivation of the period-3 forecast and subsequent copied forecasts

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    D7 is entered as =CC2∗C62*C6+DD2∗D62*D6.

  2. Diagram
    Observation

    After entry, D7 displays 46.4.

  3. Audio
    Observation

    The narrator describes the formula and then drags the handle down to period 7.

Numerical verification
Steps
  1. Expression
    F2=A1=48F_2=A_1=48
    Explanation

    Period 2 is initialized directly from the first actual demand because no prior forecast is supplied.

    Justification

    Initialization rule stated in the video.

    Shown in the video
  2. Expression
    F3=αA2+(1−α)F2F_3=\alpha A_2+(1-\alpha)F_2
    Explanation

    The period-3 forecast is formed from the period-2 actual and the period-2 forecast.

    Justification

    Exponential smoothing update formula shown on screen.

    Shown in the video
  3. Expression
    F3=0.4×44+0.6×48F_3=0.4\times 44+0.6\times 48
    Explanation

    Substitute α=0.4α=0.4, A2=44A_2=44, and F2=48F_2=48 into the update formula.

    Justification

    Values are read from cells C2, D2, C6, and D6 in the worksheet.

    Derived from the video
  4. Expression
    F3=17.6+28.8=46.4F_3=17.6+28.8=46.4
    Explanation

    The arithmetic yields the displayed forecast in cell D7.

    Justification

    Direct numerical evaluation matches the worksheet output.

    Derived from the video
  5. ExpressionCopy \text{Copy } =CC2∗C62*C6+DD2∗D6 down to row 112*D6 \text{ down to row 11}
    Explanation

    Dragging the fill handle applies the same recurrence to periods 4 through 7, producing 43.84, 46.304, 42.5824, and 42.34944.

    Justification

    Relative references advance row by row while absolute references keep the parameters fixed.

    Shown in the video
Conclusion

The worksheet generates forecasts F3F_3 through F7F_7 by repeated application of the exponential smoothing recurrence after initializing F2=48F_2=48.

Derivation of absolute and squared error columns

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    E6 is =ABS(C6-D6) and F6 is =E62E6^2.

  2. Diagram
    Observation

    Filled columns show |Error| values 4, 6.4, 6.16, 9.304, 0.5824, 0.65056 and Error² values 16, 40.96, 37.9456, 86.56442, 0.33919, 0.423228.

Uncertainties
  1. The exact completion instant of the last Error² fill is at the clip boundary.

Numerical verification
Steps
  1. Expression
    ∣e2∣=∣44−48∣=4|e_2|=|44-48|=4
    Explanation

    For period 2, subtract the forecast from demand and take absolute value.

    Justification

    Formula =ABS(C6-D6) entered in the worksheet.

    Shown in the video
  2. Expression
    ∣e3∣=∣40−46.4∣=6.4|e_3|=|40-46.4|=6.4
    Explanation

    The same rowwise operation is applied to period 3.

    Justification

    Copied formula down column E.

    Shown in the video
  3. Expression
    e22=42=16e_2^2=4^2=16
    Explanation

    Square the period-2 absolute error to populate the Error² column.

    Justification

    Formula =E62E6^2 entered in the worksheet.

    Shown in the video
  4. Expression
    e32=6.42=40.96e_3^2=6.4^2=40.96
    Explanation

    Square the period-3 absolute error similarly.

    Justification

    Copied formula down column F.

    Shown in the video
  5. Expression
    Continue down rows 8–11\text{Continue down rows 8--11}
    Explanation

    The remaining displayed values follow the same pattern for periods 4 through 7.

    Justification

    Fill-handle copying demonstrated on screen.

    Shown in the video
Conclusion

The error diagnostics are built rowwise from the demand and forecast columns, first as absolute errors and then as squared errors.

Deriving the APE column from |Error| and Demand

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    For absolute percent error, divide the absolute error by the actual value and multiply by 100. Then double-click to copy it down.

  2. Formula
    Observation

    =E6/C6∗100E6/C6*100 appears in G6.

  3. Animation
    Observation

    The formula is copied down the APE column.

Visual argument
Steps
  1. Expression
    APEi=∣Errori∣Demandi×100\text{APE}_i=\frac{|\text{Error}_i|}{\text{Demand}_i}\times 100
    Explanation

    The narrator states the rule for absolute percent error.

    Justification

    Audio definition at 00:00:02-00:00:09.

    Shown in the video
  2. Expression
    =E6/C6∗100=E6/C6*100
    Explanation

    This is the spreadsheet implementation of the rule for month 2.

    Justification

    Formula bar and cell G6 content visible at 00:00:06-00:00:12.

    Shown in the video
  3. Expression
    G6:G11 filled by copying down\text{G6:G11 filled by copying down}
    Explanation

    The same relative formula is applied to the remaining rows.

    Justification

    Animation of copying the formula down at 00:00:13-00:00:16.

    Shown in the video
Conclusion

The APE column is obtained by dividing each absolute error by the corresponding demand and multiplying by 100.

From column entries to MAD, MSE, and MAPE

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    To find MAD, we use equals average to find the mean of the absolute errors. Then drag to copy the formula for MSE and MAPE.

  2. Formula
    Observation

    =AVERAGE(E6:E11) is entered in E12.

  3. Diagram
    Observation

    E12, F12, and G12 display 4.51616, 30.37207, and 10.90941.

Visual argument
Steps
  1. Expression
    MAD=AVERAGE⁡(E6:E11)\text{MAD}=\operatorname{AVERAGE}(E6:E11)
    Explanation

    The MAD cell averages the absolute-error column.

    Justification

    Audio plus formula bar at 00:00:17-00:00:23.

    Shown in the video
  2. Expression
    MSE=AVERAGE⁡(F6:F11)\text{MSE}=\operatorname{AVERAGE}(F6:F11)
    Explanation

    Copying the average formula to the Error^2 column gives the mean squared error.

    Justification

    Drag-copy animation and displayed F12 value at 00:00:23-00:00:29.

    Derived from the video
  3. Expression
    MAPE=AVERAGE⁡(G6:G11)\text{MAPE}=\operatorname{AVERAGE}(G6:G11)
    Explanation

    Copying the average formula to the APE column gives the mean absolute percentage error.

    Justification

    Drag-copy animation and displayed G12 value at 00:00:23-00:00:29.

    Derived from the video
Conclusion

The three summary error measures are the columnwise averages of |Error|, Error^2, and APE.

Solver workflow for finding the MAD-minimizing alpha

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    Now suppose we want the best alpha that minimizes MAD... Click Min... The variable value we want to change is alpha... alpha needs to be between zero and one... Leave this method here as nonlinear. And click solve.

  2. Diagram
    Observation

    Solver Parameters shows Set Objective EE12, To Min, By Changing Variable Cells CC2, constraint CC2 <= 1, Make Unconstrained Variables Non-Negative checked, GRG Nonlinear selected.

  3. Diagram
    Observation

    Solver Results reports convergence and all constraints satisfied; C2 becomes 0.30841 and E12 becomes 4.47553.

Visual argument
Steps
  1. Expression
    min⁡ MAD(α)\min \ \text{MAD}(\alpha)
    Explanation

    Choose MAD as the objective to be minimized.

    Justification

    Audio at 00:00:52-00:01:04 and Set Objective EE12 with To: Min.

    Shown in the video
  2. Expression
    α←C2\alpha \leftarrow C2
    Explanation

    Identify the alpha cell as the changing variable.

    Justification

    Audio at 00:01:05-00:01:13 and By Changing Variable Cells CC2.

    Shown in the video
  3. Expression
    α≥0\alpha \ge 0
    Explanation

    Retain the non-negativity option for unconstrained variables.

    Justification

    Audio at 00:01:13-00:01:29 and checked Make Unconstrained Variables Non-Negative box.

    Shown in the video
  4. Expression
    α≤1\alpha \le 1
    Explanation

    Add the explicit upper-bound constraint on the alpha cell.

    Justification

    Audio at 00:01:30-00:01:52 and constraint list showing CC2 <= 1.

    Shown in the video
  5. Expression
    Method: GRG Nonlinear\text{Method: GRG Nonlinear}
    Explanation

    Leave the solving method set to nonlinear.

    Justification

    Audio at 00:01:53-00:01:56 and dropdown display.

    Shown in the video
  6. Expression
    α∗=0.30841, MAD∗=4.47553\alpha^*=0.30841,\ \text{MAD}^*=4.47553
    Explanation

    Run Solve and read the converged solution from the worksheet.

    Justification

    Solver Results dialog and updated cells at 00:01:57-00:01:59.

    Shown in the video
Conclusion

With the stated setup, Solver converges to α=0.30841\alpha = 0.30841 as the feasible value minimizing MAD in this worksheet.

Derivation of the MSE-minimizing alpha in the worksheet

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Solver Parameters displays Set Objective: FF12, To: Min, By Changing Variable Cells: CC3, Subject to the Constraints: CC3 <= 1, Solving Method: GRG Nonlinear.

  2. Audio
    Observation

    The narrator says the objective is set to MSE, other settings remain valid, and then Solve is clicked.

  3. Formula
    Observation

    After solving, C3 changes to 0.3144 and F12 changes to 29.83905.

Numerical verification
Steps
  1. Expression
    Initial state: C3=0.4,  F12=30.37207\text{Initial state: } C3=0.4,\; F12=30.37207
    Explanation

    Before rerunning Solver for MSE, the worksheet shows α=0.4α=0.4 and the corresponding MSE value.

    Justification

    Directly visible in the spreadsheet at about 13–15 seconds.

    Shown in the video
  2. Expression
    Set Objective: F12,To: Min,By Changing Variable Cells: C3\text{Set Objective: } F12,\quad \text{To: Min},\quad \text{By Changing Variable Cells: } C3
    Explanation

    The optimization target is changed to the MSE cell while keeping α as the decision variable.

    Justification

    Visible in the Solver Parameters dialog and stated in the narration.

    Shown in the video
  3. Expression
    C3≤1C3 \le 1
    Explanation

    The upper-bound constraint on α is retained from the previous setup.

    Justification

    Visible in Solver Parameters under Subject to the Constraints.

    Shown in the video
  4. Expression
    Solving Method: GRG Nonlinear\text{Solving Method: GRG Nonlinear}
    Explanation

    The nonlinear solver engine is selected for this optimization.

    Justification

    Visible in the Solver Parameters dialog.

    Shown in the video
  5. Expression
    Result: C3=0.3144,  F12=29.83905\text{Result: } C3=0.3144,\; F12=29.83905
    Explanation

    After clicking Solve, the worksheet updates to the reported optimum for MSE.

    Justification

    Visible in Solver Results and the updated spreadsheet cells.

    Shown in the video
Conclusion

The numerical Solver run demonstrates that, for this dataset and spreadsheet formulation, the MSE-minimizing smoothing constant is approximately α=0.3144\alpha=0.3144.

Derivation of the MAPE-minimizing alpha in the worksheet

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Solver Parameters displays Set Objective: GG12, To: Min, By Changing Variable Cells: CC3, Subject to the Constraints: CC3 <= 1, Solving Method: GRG Nonlinear.

  2. Audio
    Observation

    The narrator says: 'Doing the same for MAPE, we obtain point three zero eight four, just like with MAD.'

  3. Formula
    Observation

    Solver Results then shows C3=0.30841C3=0.30841.

Uncertainties
  1. The intermediate click sequence is brief, but the objective change to G12 and the resulting α value are visible.

Numerical verification
Steps
  1. Expression
    Reset state before MAPE run: C3=0.4,  G12=10.90941\text{Reset state before MAPE run: } C3=0.4,\; G12=10.90941
    Explanation

    Before optimizing MAPE, the worksheet again shows α=0.4α=0.4 and the corresponding MAPE.

    Justification

    Visible in the spreadsheet around 33–35 seconds.

    Shown in the video
  2. Expression
    Set Objective: G12,To: Min,By Changing Variable Cells: C3\text{Set Objective: } G12,\quad \text{To: Min},\quad \text{By Changing Variable Cells: } C3
    Explanation

    The objective cell is switched to MAPE while the same changing cell is used.

    Justification

    Visible in Solver Parameters.

    Shown in the video
  3. Expression
    C3≤1C3 \le 1
    Explanation

    The same upper-bound constraint on α is kept.

    Justification

    Visible in Solver Parameters.

    Shown in the video
  4. Expression
    Result: C3=0.30841\text{Result: } C3=0.30841
    Explanation

    After solving, α returns to the value previously associated with the MAD optimum.

    Justification

    Visible in Solver Results and the updated C3 cell.

    Shown in the video
Conclusion

The numerical Solver run shows that minimizing MAPE for this example gives α≈0.3084\alpha \approx 0.3084, which the narrator notes is the same as for MAD.

Worked examples · 5

Seven-month demand example used throughout the clip

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    The worksheet lists Month 1 through 7 with Demand values 48, 44, 40, 50, 37, 42, 43.

  2. Audio
    Observation

    The narrator says he will calculate exponential smoothing forecasts for this time series data in Excel.

Problem

Given monthly demand values 48, 44, 40, 50, 37, 42, 43 and α=0.4α=0.4, compute exponential smoothing forecasts and the associated absolute and squared errors in Excel.

Given
  1. Months 1 through 7 are listed.

  2. Demand values are 48, 44, 40, 50, 37, 42, 43.

  3. α is set to 0.4 and 1-α to 0.6.

  4. No initial forecast is supplied for period 1.

Goal

Populate the Forecast, |Error|, and Error² columns for the example dataset.

Steps
  1. Expression
    F2=A1=48F_2=A_1=48
    Explanation

    Initialize the second-period forecast with the first actual value.

    Justification

    Stated initialization rule in the video.

    Shown in the video
  2. Expression
    Ft=0.4At−1+0.6Ft−1(t=3,…,7)F_t=0.4A_{t-1}+0.6F_{t-1}\quad(t=3,\dots,7)
    Explanation

    Apply the exponential smoothing recurrence to obtain later forecasts.

    Justification

    Displayed formula and entered Excel formula.

    Shown in the video
  3. Expression
    (F3,F4,F5,F6,F7)=(46.4,43.84,46.304,42.5824,42.34944)(F_3,F_4,F_5,F_6,F_7)=(46.4,43.84,46.304,42.5824,42.34944)
    Explanation

    These are the forecast values shown after filling the column.

    Justification

    Visible worksheet outputs.

    Shown in the video
  4. Expression
    ∣et∣=∣At−Ft∣(t=2,…,7)|e_t|=|A_t-F_t|\quad(t=2,\dots,7)
    Explanation

    Compute absolute errors row by row.

    Justification

    Formula =ABS(C6-D6) entered in Excel.

    Shown in the video
  5. Expression
    (∣e2∣,…,∣e7∣)=(4,6.4,6.16,9.304,0.5824,0.65056)(|e_2|,\dots,|e_7|)=(4,6.4,6.16,9.304,0.5824,0.65056)
    Explanation

    These are the displayed absolute error values.

    Justification

    Visible worksheet outputs.

    Shown in the video
  6. Expression
    et2=(∣et∣)2(t=2,…,7)e_t^2=(|e_t|)^2\quad(t=2,\dots,7)
    Explanation

    Square the absolute errors to form the Error² column.

    Justification

    Formula =E62E6^2 entered in Excel.

    Shown in the video
  7. Expression
    (e22,…,e72)=(16,40.96,37.9456,86.56442,0.33919,0.423228)(e_2^2,\dots,e_7^2)=(16,40.96,37.9456,86.56442,0.33919,0.423228)
    Explanation

    These are the displayed squared error values.

    Justification

    Visible worksheet outputs.

    Shown in the video
Answer

Forecasts: 48, 46.4, 43.84, 46.304, 42.5824, 42.34944 for periods 2 through 7. Absolute errors: 4, 6.4, 6.16, 9.304, 0.5824, 0.65056. Squared errors: 16, 40.96, 37.9456, 86.56442, 0.33919, 0.423228.

Verification

Each displayed number matches direct substitution into the stated formulas using the worksheet’s demand values and α=0.4α=0.4.

Worked APE entry for month 2

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Month 2 row shows Demand = 44, Forecast = 48, |Error| = 4, and the formula =E6/C6∗100E6/C6*100 in the APE cell.

  2. Diagram
    Observation

    The resulting APE value displayed is 9.090909.

Problem

Compute the absolute percentage error for the month with demand 44 and forecast 48.

Given
  1. Demand=44\text{Demand}=44

  2. Forecast=48\text{Forecast}=48

  3. |Error\text{Error}|=4

Goal

Find APE for that row.

Steps
  1. Expression
    APE=444×100\text{APE}=\frac{4}{44}\times 100
    Explanation

    Apply the stated APE rule using the absolute error and actual demand.

    Justification

    Audio definition plus visible formula =E6/C6∗100E6/C6*100.

    Shown in the video
  2. Expression
    =9.090909=9.090909
    Explanation

    The spreadsheet displays the evaluated percentage.

    Justification

    Visible result in the APE column.

    Shown in the video
Answer

9.090909

Verification

The displayed cell value matches the direct calculation 4/44∗1004/44*100.

Initial MAD, MSE, and MAPE for alpha = 0.4

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Before optimization, the summary row shows MAD = 4.51616, MSE = 30.37207, MAPE = 10.90941.

  2. Formula
    Observation

    =AVERAGE(E6:E11) is used for MAD and then copied across.

Problem

Read the initial error summaries after the average formulas are entered.

Given
  1. α=0.4\alpha=0.4

  2. |Error| column values are present

  3. Error^2 column values are present

  4. APE column values are present

Goal

Determine MAD, MSE, and MAPE for the initial worksheet state.

Steps
  1. Expression
    MAD=4.51616\text{MAD}=4.51616
    Explanation

    Average of the |Error| column is shown in E12.

    Justification

    Visible formula result at 00:00:23.

    Shown in the video
  2. Expression
    MSE=30.37207\text{MSE}=30.37207
    Explanation

    Average of the Error^2 column is shown in F12 after copying the formula.

    Justification

    Visible result at 00:00:27-00:00:29.

    Shown in the video
  3. Expression
    MAPE=10.90941\text{MAPE}=10.90941
    Explanation

    Average of the APE column is shown in G12 after copying the formula.

    Justification

    Visible result at 00:00:27-00:00:29.

    Shown in the video
Answer

MAD = 4.51616, MSE = 30.37207, MAPE = 10.90941

Verification

These values are directly displayed in the summary row before Solver is run.

Finding the best alpha by minimizing MAD in Solver

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    Suppose we want the best alpha that minimizes MAD.

  2. Diagram
    Observation

    Solver Parameters are set to minimize EE12 by changing CC2 with CC2 <= 1 and non-negativity enabled.

  3. Diagram
    Observation

    After solving, C2=0.30841C2 = 0.30841, D2=0.69159D2 = 0.69159, MAD = 4.47553, MSE = 29.84198, MAPE = 10.88013.

Problem

Use Excel Solver to determine the alpha value that minimizes MAD subject to 0≤α≤10 \le \alpha \le 1.

Given
  1. Objective cell is MAD in EE12.

  2. Changing cell is alpha in CC2.

  3. Constraints are α≥0\alpha \ge 0 and α≤1\alpha \le 1.

  4. Solving method is GRG Nonlinear.

Goal

Find the optimal alpha and the corresponding minimized MAD.

Steps
  1. Expression
    min⁡ MAD(α)\min \ \text{MAD}(\alpha)
    Explanation

    Set the Solver objective to the MAD cell and choose Min.

    Justification

    Audio and Solver Parameters display.

    Shown in the video
  2. Expression
    Changing Variable Cells: C2\text{Changing Variable Cells}:\ C2
    Explanation

    Tell Solver to vary the alpha cell.

    Justification

    Audio and Solver Parameters display.

    Shown in the video
  3. Expression
    0≤α≤10 \le \alpha \le 1
    Explanation

    Enforce the admissible range for the smoothing constant.

    Justification

    Checked non-negativity box plus explicit CC2 <= 1 constraint.

    Shown in the video
  4. Expression
    α∗=0.30841\alpha^*=0.30841
    Explanation

    Solver updates the alpha cell to the reported optimum.

    Justification

    Post-solve worksheet display.

    Shown in the video
  5. Expression
    MAD∗=4.47553\text{MAD}^*=4.47553
    Explanation

    The minimized MAD is shown in the objective cell after solving.

    Justification

    Post-solve worksheet display.

    Shown in the video
Answer

α∗=0.30841\alpha^*=0.30841,MAD∗=4.47553\quad \text{MAD}^*=4.47553

Verification

Solver Results states that the solution converged and all constraints are satisfied.

Finding the best exponential-smoothing alpha with Excel Solver

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The worksheet shows Demand values 48, 44, 40, 50, 37, 42, 43 and summary metrics MAD, MSE, MAPE in row 12.

  2. Audio
    Observation

    The narrator walks through finding the best alpha for MAD, MSE, and MAPE using Solver.

Uncertainties
  1. The underlying forecast recursion is not explicitly written out in the clip.

Problem

Given a historical demand series in Excel and an exponential smoothing forecast table, determine the smoothing constant α\alpha that minimizes each of MAD, MSE, and MAPE using Solver.

Given
  1. Monthly demand values shown in column B: 48, 44, 40, 50, 37, 42, 43.

  2. α\alpha is stored in cell C3 and 1−α1-\alpha in D3.

  3. Error columns are |Error|, Error², and APE.

  4. Summary cells are E12=MAD, F12=MSE, G12=MAPE.

  5. Solver constraint shown: C3≤1C3 \le 1.

  6. Make Unconstrained Variables Non-Negative is checked.

  7. Solving Method: GRG Nonlinear.

Goal

Identify the optimal α\alpha for minimizing MAD, then MSE, then MAPE.

Steps
  1. Expression
    α≈0.3084withMAD=4.47553\alpha \approx 0.3084 \quad \text{with} \quad \text{MAD}=4.47553
    Explanation

    The clip opens on a completed Solver result for MAD, and the narrator states that this alpha gives the smallest MAD.

    Justification

    Audio plus visible Solver Results and spreadsheet values at 0–11 seconds.

    Shown in the video
  2. Expression
    Set Objective: F12,  Min,  Changing Cell: C3,  C3≤1\text{Set Objective: } F12,\; \text{Min},\; \text{Changing Cell: } C3,\; C3 \le 1
    Explanation

    To optimize MSE, the objective cell is changed to F12 while keeping the same decision variable and constraint.

    Justification

    Visible in Solver Parameters at about 15–24 seconds.

    Shown in the video
  3. Expression
    α=0.3144withMSE=29.83905\alpha = 0.3144 \quad \text{with} \quad \text{MSE}=29.83905
    Explanation

    After clicking Solve, the worksheet updates to the MSE-optimal solution.

    Justification

    Visible in Solver Results and updated cells at about 25–33 seconds.

    Shown in the video
  4. Expression
    Set Objective: G12,  Min,  Changing Cell: C3,  C3≤1\text{Set Objective: } G12,\; \text{Min},\; \text{Changing Cell: } C3,\; C3 \le 1
    Explanation

    To optimize MAPE, the objective cell is changed to G12 while retaining the same setup otherwise.

    Justification

    Visible in Solver Parameters at about 35–37 seconds.

    Shown in the video
  5. Expression
    α≈0.3084\alpha \approx 0.3084
    Explanation

    The MAPE run returns the same alpha value reported for MAD.

    Justification

    Narration plus visible Solver Results at about 38–43 seconds.

    Shown in the video
Answer

For the displayed example: minimizing MAD gives α≈0.3084\alpha \approx 0.3084; minimizing MSE gives α≈0.3144\alpha \approx 0.3144; minimizing MAPE gives α≈0.3084\alpha \approx 0.3084.

Verification

Each answer is verified by the corresponding Solver output screen and the updated spreadsheet cells showing the chosen objective value after optimization.

Visual events · 13

Initial worksheet setup and task statement

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    The screen shows an Excel workbook titled Exponential Smoothing - Excel.xlsx with α and 1-α at the top, a monthly demand table, empty Forecast, |Error|, Error², and APE columns, and summary labels MAD, MSE, MAPE below.

  2. Caption evidence
    Observation

    Overlay text reads: Exponential Smoothing in Excel and Finding best α using Solver.

Objects
  1. Parameter cells C1:C2 and D1:D2

  2. Monthly table with Month, Demand, Forecast, |Error|, Error², APE

  3. Summary labels MAD, MSE, MAPE

  4. Title overlays

Changes
  1. The title overlay appears over the static worksheet.

  2. Red highlight boxes move among the demand column, α cell, and error-related headers as the narrator introduces the task.

Invariants
  1. The underlying demand data remain unchanged during the introduction.

  2. α stays at 0.4 and 1-α stays at 0.6.

Interpretation

The visual layout establishes the forecasting problem, the parameter location, and the error metrics that will be computed.

Visual explanation of the starting forecast rule

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Blue boxes display F1=A1F1 = A1 and then F2=A1F2 = A1 while the cursor moves around the first two rows of the table.

Objects
  1. Blue formula overlays

  2. Rows for months 1 and 2

  3. Demand and Forecast columns

Changes
  1. The overlay first states F1=A1F1 = A1, then changes to F2=A1F2 = A1.

  2. Cell D6 is prepared to receive the value from C5.

Invariants
  1. The demand values in column C do not change.

  2. The parameter cells remain fixed at 0.4 and 0.6.

Interpretation

The animation encodes the initialization convention: absent a prior forecast, the first actual value seeds the forecast sequence and is reused for period 2.

Copying the recurrence down the forecast column

Clear evidence
Shown in the video
Evidence
  1. Animation
    Observation

    After D7 evaluates to 46.4, the fill handle is dragged downward through row 11.

  2. Diagram
    Observation

    Forecast values appear sequentially in D8:D11 as 43.84, 46.304, 42.5824, 42.34944.

Objects
  1. Cell D7 formula

  2. Fill handle

  3. Forecast column D

Changes
  1. One manually entered forecast formula is propagated to later periods.

  2. New forecast values populate rows 8 through 11 in order.

Invariants
  1. The absolute references CC2 and DD2 stay fixed.

  2. The relative references to prior demand and forecast shift down one row at a time.

Interpretation

The drag operation demonstrates how a single recurrence relation generates the whole forecast path once the initial condition is set.

Populating absolute-error and squared-error columns

Clear evidence
Shown in the video
Evidence
  1. Animation
    Observation

    The user enters =ABS(C6-D6) in E6, then fills column E downward; next enters =E62E6^2 in F6 and fills column F downward.

  2. Diagram
    Observation

    Columns E and F populate with the displayed error and squared-error values.

Uncertainties
  1. The very last squared-error fill completes at the end boundary of the clip.

Objects
  1. Column E header |Error|

  2. Column F header Error²

  3. Formula bars for E6 and F6

Changes
  1. Column E fills from row 6 to row 11 with absolute errors.

  2. Column F then fills from row 6 to row 11 with squared errors.

Invariants
  1. Demand and forecast columns remain unchanged while error columns are computed.

  2. The formulas are copied without altering their row-relative structure.

Interpretation

The visual sequence shows the standard diagnostic workflow: first compute forecast deviations, then transform them into squared deviations for later summary measures.

Static spreadsheet layout used throughout the clip

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    The worksheet shows headers α and 1-α in row 1, values 0.4 and 0.6 in row 2, and a table with Month, Demand, Forecast, |Error|, Error^2, APE from rows 4-11, with MAD, MSE, MAPE in row 13.

Objects
  1. Header cells C1:D2

  2. Forecast table rows 4-11

  3. Summary row 13

Invariants
  1. The table structure remains the same throughout the clip.

  2. Column order stays Month, Demand, Forecast, |Error|, Error^2, APE.

Interpretation

The visual layout organizes the data so that each error measure can be computed columnwise and then summarized in one row.

Copying the APE formula down the table

Clear evidence
Shown in the video
Evidence
  1. Animation
    Observation

    The cursor enters =E6/C6∗100E6/C6*100 in G6 and copies it down the APE column.

  2. Diagram
    Observation

    New APE values appear row by row, ending with 9.090909, 16, 12.32, 25.14595, 1.386667, 1.51293.

Objects
  1. Cell G6

  2. APE column G

  3. Rows 6-11

Changes
  1. The APE column changes from blank to filled with percentage values.

  2. The formula is replicated downward using relative references.

Invariants
  1. The underlying Demand and |Error| values do not change during this step.

Interpretation

The animation demonstrates that APE is a rowwise transformation of absolute error and demand.

Creating the MAD, MSE, and MAPE summary row

Clear evidence
Shown in the video
Evidence
  1. Animation
    Observation

    =AVERAGE(E6:E11) is entered in E12, then dragged across to F12 and G12.

  2. Diagram
    Observation

    Summary values 4.51616, 30.37207, and 10.90941 appear under MAD, MSE, and MAPE.

Objects
  1. Cells E12:G12

  2. Columns E, F, G

Changes
  1. The summary row changes from empty to populated with three averages.

  2. The same averaging operation is applied across adjacent error columns.

Invariants
  1. The source columns |Error|, Error^2, and APE remain unchanged during this step.

Interpretation

The visual sequence shows that MAD, MSE, and MAPE are obtained by averaging their respective column entries.

Configuring the Solver optimization problem

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Solver Parameters opens and is filled with Set Objective EE12, To Min, By Changing Variable Cells CC2, constraint CC2 <= 1, Make Unconstrained Variables Non-Negative checked, GRG Nonlinear selected.

  2. Animation
    Observation

    Red highlight boxes emphasize the objective, variable cell, constraint area, and solving method as they are discussed.

Objects
  1. Solver Parameters dialog

  2. Cell EE12

  3. Cell CC2

  4. Constraint list

  5. Solving Method dropdown

Changes
  1. The objective field becomes EE12.

  2. The direction changes to Min.

  3. The changing-variable field becomes CC2.

  4. The constraint CC2 <= 1 is added.

  5. The solving method remains GRG Nonlinear.

Invariants
  1. The worksheet data behind the dialog stays visible and structurally unchanged.

Interpretation

The dialog visually encodes the mathematical program: minimize MAD over alpha subject to 0 <= alpha <= 1.

Worksheet update after Solver converges

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Solver Results appears, then the worksheet updates C2 to 0.30841, D2 to 0.69159, and the summary row to MAD 4.47553, MSE 29.84198, MAPE 10.88013.

Objects
  1. Cells C2 and D2

  2. Summary cells E12:G12

  3. Solver Results dialog

Changes
  1. Alpha changes from 0.4 to 0.30841.

  2. 1-alpha changes from 0.6 to 0.69159.

  3. MAD changes from 4.51616 to 4.47553.

  4. MSE changes from 30.37207 to 29.84198.

  5. MAPE changes from 10.90941 to 10.88013.

Invariants
  1. The solver message states that all constraints are satisfied.

Interpretation

The final visual update shows the effect of reoptimizing alpha on both the parameter cells and all downstream error summaries.

Solver result display for the MAD optimization

Clear evidence
Shown in the video
Evidence
  1. Animation
    Observation

    A Solver Results dialog overlays the worksheet while C3=0.30841C3=0.30841 and E12=4.47553E12=4.47553 are visible.

  2. Formula
    Observation

    The word Minimum appears briefly near the MAD area around 5–7 seconds.

Uncertainties
  1. The brief appearance of the word Minimum is visible but not accompanied by a full explanatory sentence in this clip.

Objects
  1. Solver Results dialog

  2. Cell C3 with α=0.30841α=0.30841

  3. Cell D3 with 1−α=0.691591-α=0.69159

  4. Row 12 summary metrics MAD, MSE, MAPE

Changes
  1. The dialog confirms convergence to the current solution.

  2. The spreadsheet remains on the MAD-optimal state while the narrator explains the result.

Invariants
  1. The demand series in column B does not change.

  2. The constraint structure from Solver is implied to remain the same.

Interpretation

This visual establishes the MAD-optimal smoothing constant and links it to the minimized MAD value shown in the worksheet.

Solver setup for minimizing MSE

Clear evidence
Shown in the video
Evidence
  1. Animation
    Observation

    The Solver Parameters dialog opens and shows Set Objective FF12, To: Min, By Changing Variable Cells CC3, Subject to the Constraints CC3 <= 1, and GRG Nonlinear.

Objects
  1. Solver Parameters dialog

  2. Objective field

  3. Changing Variable Cells field

  4. Constraints list

  5. Solving Method dropdown

Changes
  1. The objective cell is set to F12 (MSE).

  2. The Min option is selected.

  3. The changing cell remains C3.

  4. The constraint C3 <= 1 is displayed.

Invariants
  1. The same worksheet data and error table remain in the background.

  2. The optimization variable is still α in C3.

Interpretation

The visual demonstrates how to redirect the same Solver model from one error criterion to another by changing only the objective cell.

Solver result display for the MSE optimization

Clear evidence
Shown in the video
Evidence
  1. Animation
    Observation

    After Solve is clicked, Solver Results reports a found solution and the worksheet updates to C3=0.3144C3=0.3144, D3=0.6856D3=0.6856, F12=29.83905F12=29.83905.

Objects
  1. Solver Results dialog

  2. Updated cells C3, D3, and F12

Changes
  1. α changes from 0.4 to 0.3144.

  2. MSE changes from 30.37207 to 29.83905.

  3. The dialog states that all constraints and optimality conditions are satisfied.

Invariants
  1. The demand data and table layout remain unchanged.

  2. The constraint set is the same as in the preceding setup.

Interpretation

This visual confirms the numerical outcome of the MSE minimization run.

Misconceptions · 6

Forgetting absolute references when copying parameterized formulas

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator emphasizes pressing F4 and says the dollar signs ensure the alpha cell is locked down when copying the formula to other cells.

Misconception

When a formula uses a separate parameter cell such as α, one might copy it downward without locking the parameter reference.

Clarification

The video stresses using CC2 and DD2 so the smoothing constants stay fixed while the period-specific demand and forecast references move row by row.

Assuming a separate initial forecast must always be supplied

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator explains what to do if you are not given a forecast for the first period.

  2. Diagram
    Observation

    Overlays show F1=A1F1 = A1 and F2=A1F2 = A1.

Misconception

Learners may think exponential smoothing cannot start unless an external forecast for period 1 is provided.

Clarification

This clip demonstrates a common fallback: if no initial forecast is given, use the first actual value as the seed and carry it into period 2.

Assuming one alpha optimizes all error measures

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    Note that the best alpha that will minimize MAD may differ from the one that will minimize MSE.

Misconception

That the alpha minimizing MAD is automatically the same as the alpha minimizing MSE.

Clarification

The video explicitly warns that different error criteria can lead to different optimal alpha values.

Using the forecast instead of the actual value in APE

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    For absolute percent error, divide the absolute error by the actual value and multiply by 100.

  2. Formula
    Observation

    The implemented formula is =E6/C6∗100E6/C6*100, using column C (Demand) in the denominator.

Misconception

That APE should divide the absolute error by the forecast value.

Clarification

The demonstrated formula divides by the actual demand value in column C, not by the forecast in column D.

Assuming one alpha is optimal for all error metrics

Clear evidence
Derived from the video
Evidence
  1. Audio
    Observation

    The narrator separately finds different optima: 0.3084 for MAD, 0.3144 for MSE, and 0.3084 for MAPE.

  2. Formula
    Observation

    The worksheet shows distinct objective cells E12, F12, and G12 being minimized.

Misconception

One might assume that the same smoothing constant is always optimal regardless of whether MAD, MSE, or MAPE is being minimized.

Clarification

In this example, MSE produces a slightly different optimal alpha (0.31440.3144) than MAD and MAPE (0.30840.3084), so the best α\alpha depends on the chosen error criterion.

Thinking this Excel optimization must use a linear solver

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Solver Parameters explicitly shows Solving Method: GRG Nonlinear for these optimization runs.

Misconception

A viewer might think the problem is handled with a linear programming solver because the interface is simple and tabular.

Clarification

The clip shows the GRG Nonlinear engine being used, indicating the optimization is treated as a smooth nonlinear problem in Excel Solver.

Concept relations · 14

Initialization rule when no prior forecast is supplied → One-step exponential smoothing forecast formula

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator first explains the initialization rule and then says the first calculation is therefore in the third period.

  2. Formula
    Observation

    D6 is set from C5 before D7 uses the recurrence with row 6 values.

Prerequisite
Explanation

The recurrence can only begin at period 3 after the video’s initialization rule supplies F2F_2 from A1A_1.

Using absolute references for parameters in Excel → One-step exponential smoothing forecast formula

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    The entered formula is =CC2∗C62*C6+DD2∗D62*D6.

  2. Audio
    Observation

    The narrator explains that the dollar signs lock the alpha cell when copying the formula.

Application
Explanation

Absolute referencing is the Excel mechanism that lets the same exponential smoothing formula be copied down the column without changing the parameter cells.

One-step exponential smoothing forecast formula → Absolute forecast error in Excel

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Column E uses =ABS(C6-D6), directly referencing the demand and forecast columns.

  2. Diagram
    Observation

    The |Error| column is filled only after the Forecast column has values.

Prerequisite
Explanation

Absolute error computation requires the forecast series to have been generated first.

Absolute forecast error in Excel → Squared forecast error from the absolute error column

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Column F uses =E62E6^2, taking the already computed |Error| values as input.

  2. Audio
    Observation

    The narrator says to square the absolute error.

Prerequisite
Explanation

The squared-error column is built directly from the absolute-error column in the demonstrated workflow.

APE→MAPE\text{APE} \to \text{MAPE}

Clear evidence
Supplementary explanation
Evidence
  1. Diagram
    Observation

    The table includes a rowwise APE column and a separate summary label MAPE below the table.

Uncertainties
  1. This relationship is not explicitly discussed in the audio within the clip.

Contrast
Explanation

Editorial clarification: APE denotes the per-period absolute percentage error column, whereas MAPE is the aggregate mean of such percentages shown only as a summary label here.

Absolute Percentage Error (APE) → Computing MSE and MAPE by extending the average formula

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    APE is computed rowwise in column G, then MAPE is obtained by averaging column G in cell G12.

Prerequisite
Explanation

MAPE is built from the rowwise APE values, so the APE formula must be established before the average can produce MAPE.

|Error\text{Error}| → Mean Absolute Deviation (MAD)

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    To find MAD, we use equals average to find the mean of the absolute errors.

  2. Formula
    Observation

    =AVERAGE(E6:E11) references the |Error| column.

Prerequisite
Explanation

MAD is defined in the video as the average of the absolute errors, so the |Error| column is a direct prerequisite.

Mean Absolute Deviation (MAD) → Solver setup for minimizing MAD with respect to alpha

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Solver Parameters sets the objective to EE12, the MAD cell.

  2. Audio
    Observation

    Suppose we want the best alpha that minimizes MAD.

Application
Explanation

The MAD measure computed earlier becomes the objective function minimized by Solver.

Constraint 0≤α≤10 \le \alpha \le 1 in Solver → Solver setup for minimizing MAD with respect to alpha

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    Alpha needs to be between zero and one.

  2. Diagram
    Observation

    Solver uses non-negativity plus CC2 <= 1.

Proof dependency
Explanation

The Solver optimization is meaningful only under the stated feasible region 0 <= alpha <= 1 for the smoothing constant.

Mean Absolute Deviation (MAD) → MSE\text{MSE}

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The best alpha that will minimize MAD may differ from the one that will minimize MSE.

Contrast
Explanation

The video contrasts MAD and MSE as alternative optimization criteria that can yield different optimal alpha values.

Exponential smoothing parameter selection context → Forecast error metrics used for tuning alpha

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Changing C3 updates Forecast, |Error|, Error², APE, and the summary cells MAD, MSE, MAPE.

  2. Audio
    Observation

    The narrator discusses selecting alpha to minimize each metric.

Application
Explanation

The smoothing constant α\alpha is the input whose value determines the forecast errors summarized by MAD, MSE, and MAPE.

Forecast error metrics used for tuning alpha → Using Excel Solver to optimize alpha

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    Solver objective cells are set to E12, F12, or G12 depending on the metric being minimized.

Prerequisite
Explanation

Understanding what MAD, MSE, and MAPE measure is required before choosing one of them as the Solver objective.

Find an answer · 18

What does α represent in this exponential smoothing worksheet and what value is used in the example?

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Cells C1:C2 show α=0.4α=0.4.

  2. Audio
    Observation

    The narrator calls 0.4 the chosen alpha value.

Knowledge points
  1. α\alpha
  2. One-step exponential smoothing forecast formula

Why does the first exponential smoothing calculation begin in period 3 rather than period 2?

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator says the first calculation is therefore in the third period.

  2. Diagram
    Observation

    Overlays show F1=A1F1 = A1 and F2=A1F2 = A1.

Knowledge points
  1. Initialization rule when no prior forecast is supplied
  2. One-step exponential smoothing forecast formula

Why are CC2 and DD2 used instead of C2 and D2 in the forecast formula?

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The narrator explains that the dollar signs lock the alpha cell when copying the formula.

  2. Formula
    Observation

    =CC2∗C62*C6+DD2∗D62*D6 is visible in the formula bar.

Knowledge points
  1. Using absolute references for parameters in Excel
  2. One-step exponential smoothing forecast formula

How does dragging the fill handle generate the remaining forecasts from one formula?

Clear evidence
Shown in the video
Evidence
  1. Animation
    Observation

    The fill handle is dragged from D7 down to D11.

  2. Diagram
    Observation

    Forecast values appear for periods 4 through 7.

Knowledge points
  1. One-step exponential smoothing forecast formula
  2. Using absolute references for parameters in Excel

What Excel formulas are used to compute |Error| and Error² in this example?

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    E6 uses =ABS(C6-D6) and F6 uses =E62E6^2.

  2. Audio
    Observation

    The narrator describes absolute errors and then squaring the absolute error.

Knowledge points
  1. Absolute forecast error in Excel
  2. Squared forecast error from the absolute error column

Is the APE calculation demonstrated within this 120-second segment?

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    The APE header is visible but no APE formula or values appear before the clip ends.

Knowledge points
  1. APE\text{APE}

How is APE calculated in the spreadsheet?

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    For absolute percent error, divide the absolute error by the actual value and multiply by 100.

Knowledge points
  1. Absolute Percentage Error (APE)
  2. APE\text{APE}

What Excel formula is used to compute MAD?

Clear evidence
Shown in the video
Evidence
  1. Formula
    Observation

    =AVERAGE(E6:E11) is entered for MAD.

Knowledge points
  1. Mean Absolute Deviation (MAD)

How are MSE and MAPE obtained after MAD is calculated?

Clear evidence
Shown in the video
Evidence
  1. Animation
    Observation

    The average formula is dragged from MAD to MSE and MAPE.

Knowledge points
  1. Computing MSE and MAPE by extending the average formula

Why might the alpha minimizing MAD differ from the alpha minimizing MSE?

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    The best alpha that will minimize MAD may differ from the one that will minimize MSE.

Knowledge points
  1. Different error measures can imply different optimal alpha values

How do you set up Solver to minimize MAD by changing alpha?

Clear evidence
Shown in the video
Evidence
  1. Diagram
    Observation

    Solver Parameters shows objective EE12, Min, changing cell CC2.

Knowledge points
  1. Solver setup for minimizing MAD with respect to alpha

What constraints are placed on alpha in the Solver model?

Clear evidence
Shown in the video
Evidence
  1. Audio
    Observation

    Alpha needs to be between zero and one.

  2. Diagram
    Observation

    Non-negativity box and constraint CC2 <= 1 are shown.

Knowledge points
  1. Constraint 0≤α≤10 \le \alpha \le 1 in Solver
Coverage and review notes

Covered · Introduction to the worksheet, the chosen α=0.4α=0.4, and the planned error metrics.

Covered · Explanation and visual encoding of the initialization rule F1=A1F1=A1 and F2=A1F2=A1.

Covered · Entry of the exponential smoothing recurrence in Excel and propagation of forecasts through period 7.

Covered · Construction of the |Error| and Error² columns by copying formulas downward.

Covered · Defines and implements APE as |Error| / Demand * 100 and copies the formula down the column.

Covered · Computes MAD with AVERAGE and extends the same averaging method to MSE and MAPE.

Covered · Narrator warns that the alpha minimizing MAD may differ from the alpha minimizing MSE.

Covered · Opens the Data tab and launches Solver; this is procedural setup leading into the optimization model.

Covered · Sets the objective to MAD, chooses Min, and designates alpha as the changing variable.

Covered · Explains and enters the feasible range 0 <= alpha <= 1 using non-negativity plus an explicit upper-bound constraint.

Covered · Leaves GRG Nonlinear selected, runs Solve, and displays the converged solution with updated alpha and error summaries.

Covered · Opening state shows the MAD-optimal Solver result and the narrator explains that alpha about 0.3084 minimizes MAD.

Covered · Brief transition after the MAD discussion as the worksheet resets toward the next optimization setup.

Covered · Solver is reconfigured with objective F12 (MSE), run with GRG Nonlinear, and the result alpha 0.3144 is shown and narrated.

Covered · Short transition back to the base worksheet before the MAPE run.

Covered · Solver objective changes to G12 (MAPE), the run returns alpha 0.3084, and the narrator notes it matches MAD.

Covered · Closing narration summarizes that this is how to use Solver to find the best alpha for exponential smoothing.

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  • Time series and exponential smoothing ExplanationAt 0:00
    Why this connection?

    Reviewed English material v1: card/concept_card "Exponential smoothing setup in Excel" starting at 0:00 — The worksheet stores the smoothing parameters separately from the data table: α is in C2 with value 0.4, and 1-α is in D2 with value 0.6. The demand series has seven monthly observations, and the table reserves columns for Forecast, |Error|, Error², and APE, with summary labels MAD, MSE, and MAPE below.

  • Model validation and error measures ExplanationAt 2:23
    Why this connection?

    Reviewed English material v1: card/concept_card "MSE and MAPE from the same averaging pattern" starting at 2:23 — After MAD is calculated, the same average formula is dragged across to the Error^2 and APE columns. This yields MSE = 30.37207 and MAPE = 10.90941 in the initial state. MSE=1n∑Error2\text{MSE}=\frac{1}{n}\sum \text{Error}^2,MAPE=1n∑APE\quad \text{MAPE}=\frac{1}{n}\sum \text{APE}