In a test of the effectiveness of a device that is supposed to increase gasoline mileage in automobiles, a sample of cars were run, in random order, over a prescribed course both with and without the device in random order. The mileages (mpg) are given below. Is there evidence that the device is effective?

1. What is/are the population(s) of interest? Think carefully and be as specific as possible!

2. What are the research and null hypotheses?

3. What is/are the sample(s)?

4. What is the comparison distribution a distribution of?

5. What are the properties of the comparison distribution?

6. What is/are the critical value(s) of the test?

7. What is the value of the test statistic?

8. What conclusion should the researcher draw?

9. Estimate the p value of the test. You will need to state a range.

Car number 1 2 3 4 5 Mileage with device 21.0 29.7 24.6 25.2 29.9 Mileage without device 22 28.7 23.6 26.2 28.9