For this Assignment, you are working at a firm that conducts independent testing for heavy industry. Recently, an automobile manufacturer has been in the news for complaints about the highway gas mileage of their latest model minivan. You receive a contract from a consumer action group to test and write a report on the company's claim that its minivans get 28 miles per gallon on the highway. The car company agrees to allow you to select randomly 35 low-mileage fleet minivans to test their highway mileage. Your test results gave you the following data:

29.7 24.5 27.1 29.8 29.2 27.0 27.8 24.1 29.3

25.9 26.2 24.5 32.8 26.8 27.8 24.0 23.6 29.2

26.5 27.7 27.1 23.7 24.1 27.2 25.9 26.7 27.8

27.3 27.6 22.8 25.3 26.6 26.4 27.1 26.1

To prepare for this Assignment:

Part 2: Hypothesis Testing: Two-Tail Test and One-Tail Test

Complete the following and include your results and responses in your report (use alpha = 0.05):

• List the null and alternative hypotheses for the two-tail test for the mean. Calculate the observed value of the test statistic and the associated p-value
  • Is the observed test statistic in the critical region? Is the p-value higher or lower than your alpha?
• List the null and alternative hypotheses for the one-tail test of the mean. Calculate the observed value of the test statistic and the associated p-value.
  • Is the observed test statistic in the critical region? Will the p-value be higher or lower than your alpha?

Conclusions

In your report, use the confidence interval information and the results of the hypothesis testing to provide support for your conclusions and recommendations to the company. Specifically:

• What conclusions did you reach? What did you learn about the situation by using each method? Did one method offer more conclusive proof than another?
• Based on your results, do you support the company's claim that their minivans get 28 miles per gallon?
• Summarize the details of your test methods and the results from each statistical method you used. Explain the findings so that executives from both the agency and the company can understand your conclusion.
• Finally, present recommendations for actions that the company might take to use your findings to better serve their customers in the future.