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 6.9 pounds/square inch. The valve was tested on 26 engines and the mean pressure was 6.6 pounds/square inch with a standard deviation of 0.6. Is there evidence at the 0.05 level that the valve performs below the specifications? Assume the population distribution is approximately normal. Step 1 of 5: State the null and alternative hypotheses.