72. Mutual funds returns, part 2. An investor now tells you that if you leave your money in as long as 10 years, you will see an even greater return, so you would like to compare the 5-year and 10-year returns of a random sample of mutual funds to see if your return is expected to be greater if you leave your money in the funds for 10 years.

a) Using the data provided, check the conditions for this test.

b) Write the null and alternative hypotheses for this test.

c) Test the hypothesis and find the P-value if appropriate.

d) Find a 95% confidence interval for the mean difference.