In: Math
An engineer designed a valve that will regulate water pressure on an automobile engine. The engineer designed the valve such that it would produce a mean pressure of 7.2 pounds/square inch. It is believed that the valve performs above the specifications. The valve was tested on 250 engines and the mean pressure was 7.3 pounds/square inch. Assume the standard deviation is known to be 0.9. A level of significance of 0.1 will be used. Determine the decision rule.