The data for $30$ samples of three items each, from the study at Birdseye Magnetronics $($from Prob. $8-24,$ above$),$ was further analyzed in an effort to use it for process control.$$a$.$ Compute the mean and range of each sample, calculate the control limits$,$ and plot them on x and R control charts.$$b$.$ Does the process appear to be in statistical con$-$ trol? Why or why not?