An engineer has designed a valve that will regulate water pressure on an automobile engine. the valve was tested on 170 engines and the mean pressure was 4.9 lbs/square inch. assume the variance is known to be 1. if the valve was designed to produce a mean pressure of 5 lbs/square inch, is there sufficient evidence at the 0.02 level that the valve does not perform to the specifications? state the null and alternative hypotheses for the above scenario.