An engineer has designed a valve that will regulate waterpressure on an automobile engine. The valve was tested on 280engines and the mean pressure was 5.2 pounds/square inch (psi).Assume the population standard deviation is 0.8. If the valve wasdesigned to produce a mean pressure of 5.3 psi, is there sufficientevidence at the 0.01 level that the valve performs below thespecifications? Step 2 of 6 : Find the value of the test statistic.Round your answer to two decimal places.
