Question

An engineer has 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 7.2 pounds/square inch. The valve was tested on 26 engines and the mean pressure was 6.9 pounds/square inch with a standard deviation of 0.9. Is there evidence at the 0.05 level that the valve does not perform to the specifications? Assume the population distribution is approximately normal. Step 4 of 5 : Determine the decision rule for rejecting the null hypothesis. Round your answer to three decimal places.

Answer 1

Here we will apply t test for mean to test.