Software upgrade times $($in minutes$)$ are being evaluated. Samples of five observations each have been taken, and the

results are as listed.

Click here for the Excel Data File

Factors for three$-$sigma control limits for $\stackrel{}{x}$ and $R$ charts

a$.$ Using factors from above table, determine upper and lower control limits for mean and range charts.

Note: Round your intermediate calculations and final answers to $2$ decimal places. Leave no cells blank $-$ be

certain to enter $"0"$ wherever required.

b$.$ Decide if the process is in control.

The process is in control.

The process is not in control.