14.16 Hamburger sales The market research department of a chain of hamburger restaurants wants to compare the mean monthly sales of hamburgers under three different marketing strategies. It randomly assigns 15 restaurants to the three groups, five per group. The sample means for the three groups were 1800, 1500, and 1200. The table shows the ANOVA table from SPSS.

Hamburger sales Source DF SS MS F P Group 2 82.00 41.00 1.02 0.389 Error 12 481.00 40.08 Total 14 563.00

a. Report and interpret the P-value for the ANOVA F test.

b. For the Tukey 95% multiple comparison confidence intervals comparing each pair of means, calculate the margin of error. Explain why will it be same for all pairs of means.