Is there a difference in the yields of different types of investments? The file CDRate contains the

Question:

Is there a difference in the yields of different types of investments? The file CDRate contains the yields for a oneyear certificate of deposit (CD) and a five-year CD for 25 banks in the United States as of April 15, 2015. (Data extracted from www.Bankrate.com, April 15, 2015.)

a. Construct a 95% confidence interval estimate for the mean yield of one-year CDs.

b. Construct a 95% confidence interval estimate for the mean yield of five-year CDs.

c. Compare the results of (a) and (b).