Question

An automobile manufacturer claims that their jeep has a 31.3 miles/gallon (MPG) rating. An independent testing firm has been contracted to test the MPG for this jeep. After testing 140 jeeps they found a mean MPG of 31.6. Assume the variance is known to be 1.69. Is there sufficient evidence at the 0.05 level that the jeeps outperform the manufacturer's MPG rating?

Enter the hypotheses:

Enter the value of the z test statistic. Round your answer to two decimal places.

Specify if the test is one-tailed or two-tailed.

Enter the decision rule.

Enter the conclusion.

Answer 1