A company manufacturing oil seals wants to establish control charts on the process. There are 25 preliminary

Question:

A company manufacturing oil seals wants to establish control charts on the process. There are 25 preliminary samples of size 5 on the internal diameter of the seal. The summary data (in mm) are as follows: and x R

(a) Find the control limits that should be used on the x and R control charts.
(b) Assume that the 25 preliminary samples plot in control on both charts. Estimate the process mean and standard deviation.