How do the ratings of TV and Internet services compare? The file Telecom contains the rating of 14 different providers. (Data extracted from “Ratings: TV, Phone, and Internet Services,” Consumer...

How do the ratings of TV and Internet services compare? The file Telecom contains the rating of 14 different providers.

(Data extracted from “Ratings: TV, Phone, and Internet Services,”

Consumer Reports, May 2014, pp. 28–29.)

a. At the 0.05 level of significance, is there evidence of a difference in the mean service rating between TV and Internet services?

b. What assumption is necessary about the population distribution in order to perform this test?

c. Use a graphical method to evaluate the validity of the assumption in (a).

d. Construct and interpret a 95% confidence interval estimate of the difference in the mean service rating between TV and Internet services.