The intercept b0 is calculated by substituting the mean point (xˉ,yˉ) and the known slope b1 into the regression equation y^=b0+b1x, and then solving algebraically for b0. In the example, substituting x=3, y^=4, and b1=0.6 yields 4=b0+0.6(3), which simplifies to b0=2.2.
Conditions: The slope b1 has already been computed.; The sample means xˉ and yˉ are known.; The regression line is assumed to pass through (xˉ,yˉ).
The intercept b0 is calculated by substituting the mean point (xˉ,yˉ) and the known slope b1 into the regression equation y^=b0+b1x, and then solving algebraically for b0. In the example, substituting x=3, y^=4, and b1=0.6 yields 4=b0+0.6(3), which simplifies to b0=2.2.
Conditions: The slope b1 has already been computed.; The sample means xˉ and yˉ are known.; The regression line is assumed to pass through (xˉ,yˉ).
The regression line must pass through the point (3,4) because this point represents the intersection of the sample means of the independent and dependent variables, (xˉ,yˉ). The video states as a general property that all regression lines have to go through the point where the mean of the independent variable and the mean of the dependent variable cross.
Conditions: The data set has a computed mean for x, xˉ=3.; The data set has a computed mean for y, yˉ=4.; The context is simple linear regression.
The regression line must pass through the point (3,4) because this point represents the intersection of the sample means of the independent and dependent variables, (xˉ,yˉ). The video states as a general property that all regression lines have to go through the point where the mean of the independent variable and the mean of the dependent variable cross.
Conditions: The data set has a computed mean for x, xˉ=3.; The data set has a computed mean for y, yˉ=4.; The context is simple linear regression.