Chapter 8, Problem 27RP

Fuel Economy. The U.S. Department of Energy collects fuel-economy information on new motor vehicles and publishes its findings in Fuel Economy Guido. The data included are the result of vehicle testing done at the Environmental Protection Agency’s National Vehicle and Fuel Emissions Laboratory in Ann Arbor, Michigan, and by vehicle manufacturers themselves with oversight by the Environmental Protection Agency. On the WeissStats site, we provide the highway mileages, in miles per gallon (mpg), for one year’s cars. Use the technology of your choice to do the following.

1. a. Obtain a random sample of 35 of the mileages.
2. b. Use your data from part (b) and the t-interval procedure to find a 95% confidence interval for the mean highway gas mileage of all cars of the year in question.
3. c. Does the mean highway gas mileage of all cars of the year in question lie in the confidence interval that you found in part (c)? Would it necessarily have to? Explain your answers.