Why is the Year 4 forecast written as 357 instead of 357.2?

Conditions

• The raw calculated value for Year 4 is 357.2.
• The instructor applies a rounding convention to record whole numbers in the table.
• Demand is assumed to be measured in discrete units.

Reasoning, step by step

1. Calculate the exact forecast using the formula: $F_4 = 0.4(395) + 0.6(332) = 357.2$.
2. Apply the rounding rule to convert the decimal 357.2 to the nearest integer.
3. Record the rounded value, 357, in the Forecast Demand column for Year 4.

Example

The calculator displays 357.2. The instructor says, 'so we can round it off 357,' and writes 357 in the table. This shows that the stored forecast is slightly less precise than the raw computed value.

Common misconceptions

• Assuming the number written in the table is always the exact unrounded result.
• Believing that fractional demand values must be kept as decimals in the final forecast table.

Watch the explanation

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