$2\mathrm{.}44$ A factory experiencing a board$-$solder defect problem with an LED panel board product tested each board manufactured for LED failure. Data were collected on the area of the board on which LEDs were soldered for $8$ bad panels and $8$ good panels that passed the failure test.

Failure $32\mathrm{.}5,34\mathrm{.}5,33\mathrm{.}5,36\mathrm{.}5,34\mathrm{.}0,32\mathrm{.}25,33\mathrm{.}75,35\mathrm{.}25$

$($a$)$ Calculate the sample mean $\stackrel{}{x}.$

$($b$)$ Calculate the sample standard deviation $s.$