stats

A stock analyst wondered whether the mean rate of return of financial, energy and utility stocks differed over the past 5 years. He obtained a simple random sample of eight companies from each of the three sectors and obtained the 5-year rates of return shown in the following table (in percents):

(a) State the null and alternative hypothesis.

(b) Are the mean rates of return different at the alpha = 0.05 level of significance? Please explain your answer, citing numeric and other evidence in support of your response.