Question: A management consultant wants to determine whether the age and gender of a restaurant's wait staff influence the size of the tip the customer leaves. Three age brackets (factor A in columns: young, middle-age, older) and gender (factor B in rows: male, female) are used to construct a random block experiment. For each combination, the percentage of the total bill left as a tip for 10 wait staff is examined. The following ANOVA table with a = 0.01 is produced.
a. Can you conclude that there is interaction between a g e and gender at the 1% significance level?
b. Are you able to conduct tests based on the main effects? If yes, conduct these tests at the 1 % significance level. If no, explain.