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 of6.8 pounds/square inch. The valve was tested on250 engines and the mean pressure was6.9 pounds/square inch. Assume the standard deviation is known to be

0.9. Is there evidence at the 0.01 level that the valve performs above the specifications?

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.