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):

Financial	Energy	Utilities
10.76	12.72	11.88
15.05	13.91	5.86
17.01	6.43	13.46
5.07	11.19	9.90
19.50	18.79	3.95
8.16	20.73	3.44
10.38	9.60	7.11
6.75	17.40	15.70

Required:

(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.