Table : TABLE 14-15. Calculating the Sum of Squares for the First Independent Variable The sum of squares for the first independent variable is calculated by subtracting the overall mean (the grand mean) from the mean for each level of that variable—in this case, age—to create deviations, then squaring the deviations and summing them: Σ(Mrow(age) − GM)2 = 0.03.
XMrow(age) − GM(Mrow(age) − GM)2
   Y, 1   0.25   (0.16 − 0.21) = 20.05   0.0025
   0.21   (0.16 − 0.21) = 20.05   0.0025
   0.14   (0.16 − 0.21) = 20.05   0.0025
   Y, 3   0.07   (0.16 − 0.21) = 20.05   0.0025
   0.13   (0.16 − 0.21) = 20.05   0.0025
   0.16   (0.16 − 0.21) = 20.05   0.0025
   O, 1   0.27   (0.26 − 0.21) = 0.05   0.0025
   0.22   (0.26 − 0.21) = 0.05   0.0025
   0.17   (0.26 − 0.21) = 0.05   0.0025
   O, 3   0.33   (0.26 − 0.21) = 0.05   0.0025
   0.31   (0.26 − 0.21) = 0.05   0.0025
   0.26   (0.26 − 0.21) = 0.05   0.0025