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 $210$ engines and the mean pressure was $4\mathrm{.}3$

pounds$/$square inch. Assume the standard deviation is known to be

$0\mathrm{.}7.$ A level of significance of $0\mathrm{.}01$ will be used. Find the value

of the test statistic. Round your answer to $2$ decimal places. Enter

the value of the test statistic.$$