Question

An engineer designed a valve that will regulate water pressure on an automobile engine. The engineer designed the valve such that it would produce a mean pressure of 7.0 pounds/square inch. The valve was tested on 130 engines and the mean pressure was 7.2 pounds/square inch. Assume the variance is known to be 0.64. Is there evidence at the 0.05 level that the valve performs above the specifications?

Step 1 of 5: Enter the hypotheses:

Step 2 of 5: Enter the value of the z test statistic. Round your answer to two decimal places.

Step 3 of 5: Specify if the test is one-tailed or two-tailed.

Step 4 of 5: Enter the decision rule.

Step 5 of 5: Enter the conclusion.

Answer 1