Analysis of Variance for Response Source DF SS MS F P Regression 7 105.4375 15.0625 4.7255 0.0222 A 1 27.5625 27.5625 8.6471 0.0187 B 3 8.1875 2.7292 0.8562 0.5017 A*B 3 69.6875 23.2292 7.2876 0.0112 Error 8 25.5000 3.1875 Total 15 130.9375 FACTORB1 STATISTICS IN ACTION (continued) REVISITED M09_MCCL3396_14_GE_C09.indd 583 29/09/2021 14:36 584 CHAPTER 9 ● Design of Experiments and Analysis of Variance

a. Identify the treatments for this experiment. Calculate and plot the treatment means, using the response variable as the y-axis and the levels of factor B as the x-axis. Use the levels of factor A as plotting symbols. Do the treatment means appear to differ? Do the factors appear to interact?

b. The Minitab ANOVA printout for this experiment is shown. Sum the appropriate sums of squares and test to determine whether the treatment means differ at the a = .05 level of significance. Does the test support your visual interpretation from part a?

c. Does the result of the test in part b warrant a test for interaction between the two factors? If so, perform it using a = .05.

d. Do the results of the previous tests warrant tests of the two factor main effects? If so, perform them using a = .05.

e. Interpret the results of the tests. Do they support your visual interpretation from part a?