Managers’ hourly wages. What affects marketing managers’

hourly wages? To find out, mean hourly wages were retrieved from the U.S. Bureau of Labor Statistics for two managerial occupations in marketing (Sales managers, Advertising managers) for a random sample of states from three regions (Midwest, Southeast, West; www.bls.gov/

data/#wages). Here are boxplots showing mean hourly wages for the two marketing occupations and the three regions as well as the results for a two-way ANOVA.

Source DF Sum of Squares Mean Square F-ratio P-value Manager Type 1 1325.93 1325.93 31.84 60.0001 Region 2 153.55 76.78 1.84 0.176 Interaction 2 32.74 16.37 0.39 0.678 Error 30 1249.32 41.64 Total 35 2761.55

a) Is this an experiment or an observational study? Explain.

b) Are the conditions for two-way ANOVA met?

c) If so, perform the hypothesis tests and state your conclusions in terms of hourly wages, occupational type, and region.

d) Is it appropriate to interpret the main effects in this case? Explain.