Question: A quality analyst wants to construct a control chart for determining whether four machines, all producing the same product, are in control with regard to a particular quality attribute. Accordingly, she inspected $1,000$ units of output from each machine in random samples, with the following results. The estimate average proportion of defectives is $0\mathrm{.}02.$

a$.$ Find the UCL and LCL of the p$-$chart to estimate $3-$sigma in$-$control process.

b$.$ True$/$False$.$ Explain why. If a point on a control chart falls outside one of the control limits$,$ this suggests that the process output is nonrandom and should be investigated.