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 $4\mathrm{.}2$ pounds$/$square inch. It is believed that the valve performs above the specifications. The valve was tested on $150$ engines and the mean pressure was $4\mathrm{.}3$ pounds$/$square inch. Assume the standard deviation is known to be $0\mathrm{.}8.$ A level of significance of $0\mathrm{.}05$ will be used. Find the value of the test statistic. Round your answer to $2$ decimal places.

Enter the value of the test statistic.