An engineer has designed a valve that will regulate water pressure on an automobile engine. The valve was tested on 120 engines and the mean pressure was 4.7 lbs/square inch. Assume the variance is known to be 0.81. If the valve was designed to produce a mean pressure of 4.9 lbs/square inch, is there sufficient evidence at the 0.02 level that the valve performs below the specifications?

State the null and alternative hypotheses for the above scenario.

H0:

Ha: