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An engineer has designed a valve that will regulate water pressure on an automobile engine. The valve was tested on 280 engines and the mean pressure was 6 Ibs/square inch. Assume the standard deviation is known to be 0.9. If the valve was designed to produce a mean pressure of 5,9 Ibs/square inch, is there sufficient evidence at the 0.02 level that the valve performs above the specifications? State the null and alternative hypotheses for the above scenario