Question

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

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. (75–150 words, or 1–2 paragraphs)

• Is the observed test statistic in the critical region? Is the p-value higher or lower than your alpha? (75–150 words, or 1–2 paragraphs)

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. (75–150 words, or 1–2 paragraphs)

• Is the observed test statistic in the critical region? Will the p-value be higher or lower than your alpha? (75–150 words, or 1–2 paragraphs)

Answer 1