You have decided to purchase a car and have narrowed your choice down to two cars. However, you have two areas of concern. First, you want to purchase the car that gets the better gas mileage. Second, you want to purchase a car that holds its value better. To help make an informed decision, you decide to collect some data and run some tests.
(a) Decide on two cars that are similar that you would consider purchasing.
(b) Go to www.fueleconomy.gov and obtain data on the fuel economy of each car you are considering. Treat the data as a random sample of all cars.
(c) Draw side-by-side boxplots of the fuel economy to verify there are no outliers and to verify it is reasonable to conclude the data come from a population that is normally distributed (if your sample size is small).
(d) Conduct the appropriate test to determine if there is a significant difference in the gas mileage of the two cars.
(e) Go to an online website that lists used cars for sale. Obtain a matched-pairs random sample of cars where each car is paired with the second car based on age of the car and mileage. For example, if you are considering a Camry or Accord, then match a two-year-old Camry with 18,000 miles with a two-year-old Accord with 18,000 miles. However, to determine how well the car holds its value, subtract the asking price of the car from the price when the car is new.
(f) Conduct the appropriate test to determine if one car holds its value better than the other car.
(g) Write a report detailing which car you would purchase.