Practice: Testing statistical hypothesis about one population mean when sample size is small and population variance is unknown. "student's t$-$test" $($p$.289)$

$3.$ A tool assembling company believes that a worker should take no more than $30$ minutes to assemble a particular tool. A sample of $16$ workers who assembled that tool showed that the average time was $x_{?}=33$ minutes with a standard deviation of $s=6$ minutes. Test at the $=0\mathrm{.}05$ level of significance if the data provide sufficient evidence to indicate the validity of the company's belief. Assume the assembly times are normally distributed.