A stock analyst wondered whether the mean rate of return of financial, energy, and utility stocks differed over the past five years. He obtained a simple random sample of eight companies from each of the three sectors and obtained the five-year rates of return shown in the following table (in percent):

(a) State the null and alternative hypotheses.
(b) Verify that the requirements to use the one-way ANOVA procedure are satisfied. Normal probability plots indicate that the sample data come from normal populations.
(c) Are the mean rates of return different at the a = 0.05 level of significance?
(d) Draw boxplots of the three sectors to support the results obtained in part (c).