$4)$ You want to define control limits$,$ UCL and LCL$,$ for a X$-$bar Chart to control the diameter of cylinder rails. You collected $30$ samples from the manufacturing line. Each sample is of size $7.$ Assume that$$is $3\mathrm{.}311$ inches and$$is $8\mathrm{.}503$ inches. Then, UCL is inches and LCL is inches for this chart.