In order to determine whether or not a process is in control, 20 subgroups of size 6 are taken. The quality characteristic of interest is the weight of the castings, and it is found that x bar bar= 706, s bar= 1.738

a. Estimate the process mean and s. d. of the weight of the castings.

b. Assuming the process is in control find the Upper and Lower control limits for the means.

c. Assuming the process is in control find the Upper and Lower control limits for the s.ds.

d. If the specification limits are 702 and709, what proportion of the castings, do not conform to specifications?

e. Calculate the PCR and interpret.