Question

An engineer has designed a valve that will regulate water pressure on an automobile engine. The valve was tested on 110 engines and the mean pressure was 4.7 lbs/square inch. Assume the standard deviation is known to be 0.8  If the valve was designed to produce a mean pressure of 4.94 lbs/square inch, is there sufficient evidence at the 0.05 level that the valve performs below the specifications?

State the null and alternative hypotheses for the above scenario.

Answer 1