7-12. Consider the ANOVA in Exercise 7-10. (a) Calculate the sum of squares, mean squares, and F-statistic for the A, B, and AB effects. (b) How does the sum of squares of regression relate to the sum of squares for the A, B, and AB effects? (c) Assume that the current residual error is estimated from pure error. Conduct a lack-of-fit test for the pooled B effect and AB interaction effect. Would you pool these effects into residual error? Why or why not