A Random Sample of Nine Cast Aluminum Pots Is Taken

Essay

A random sample of nine cast aluminum pots is taken from a production line once every hour. The interior diameter of the pots is measured and the sample mean is calculated. The target for the diameter is 12 inches and the standard deviation for the pot diameter is 0.05 inches.
Assume the pot diameter is normally distributed.
A) Construct the centerline and the upper and lower control limits for the chart.
B) The means of the samples for a given eight-hour day are
12.01 12.06 11.97 12.08 11.92 11.95 11.97 12.04.
Plot these values on the chart.
C) Does it appear that the process is under control? Explain.