Here is textbook problem;

In an experiment to investigate the effect of color of paper (blue, green, orange) on response rates for questionnaires distributed by the "windshield method" in supermarket parking lots, 15 representative supermarket parking lots were chosen in a metropolitan area and each color was assigned at random to these lots. The response rates (in percent) follow. Assume that the one-way ANOVA model is appropriate.

Color Response rate (in percent)

Blue 21, 36, 20, 17, 54, 39

Green 32, 24, 15, 20, 19

Orange 21, 34, 17, 23, 24, 33

a. Provide aligned dot plots of the data. Do the factor level means appear to differ? Does the variability of the observations within each factor level appear to be approximately the same for all factor levels?

b. Compute the fitted values

c. Compute the residuals.

d. Conduct a test to determine whether or not the mean response rates for the three colors differ. Use level of significance=0.05

e. State the alternatives, decision rule, and conclusion.

f. When informed of the findings, an executive said: "See? I was right all along. We might as well print the questionnaires on plain white paper, which is cheaper." Does this conclusion follow from the findings of the study? Discuss.