Use the following scenario to answer the next 6 questions. An engineer has designed a valve that will regulate water pressure on an automobile engine. The valve was tested on 30 engines and the mean...

Use the following scenario to answer the next 6 questions.

An engineer has designed a valve that will regulate water pressure on an automobile engine.  The valve was tested on 30 engines and the mean pressure was 4.8 psi with a standard deviation of 1 psi.  If the valve was designed to produce an overall mean pressure of 5.0 psi, is there sufficient evidence at the 10% level of significance that the valve performs below specifications?