Refer to Exercise 12.

a. Assume that the measurements for tread A and for tread B come from independent samples, and construct a 95% confidence interval for the difference in mean tread wear using the methods of Section 10.1.

b. Which confidence interval is narrower, the one using matched pairs or the one constructed under the assumption that the samples are independent?

Explain.

Exercise 12

A tire manufacturer is interested in testing the fuel economy for two different tread patterns. Tires of each tread type were driven for 1000 miles on each of 9 different cars. The mileages, in miles per gallon, were as follows:

Transcribed Image Text:

Car Tread A Tread B 1 24.7 20.3 2 22.5 19.0 3 24.0 22.5 4 26.9 23.1 5 22.5 20.9 6 23.5 23.6 7 22.7 21.4 68 19.7 18.2 27.5 25.9