Chapter B.6, Problem 17AYU

Rates of Return 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):

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

 Source: Morningstar.com

1. (a) State the null and alternative hypotheses.
2. (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.
3. (c) Are the mean rates of return different at the α = 0.05 level of significance?
4. (d) Draw boxplots of the three sectors to support the results obtained in part (c).