To derive the Sxx variance formula, let's start with the definition of variance:
is critical in determining the relationship between two variables. In simple linear regression ( ), it is used to calculate the of the best-fit line: Sxx Variance Formula
The total SST is precisely ( S_xx ) for the entire response variable. And the variance estimate within groups is based on SSW/df, which is analogous to Sxx within each group summed. To derive the Sxx variance formula, let's start