A machine shop owner wishes to monitor the diameter of an engine boring operation where the piston bore should be 4.25”. He obtains 8 samples of 5 and records the following data. Calculate the control limits for X bar and R charts, plot the charts and indicate if the process is in control.

                                    Sample #

1         2         3         4         5          6         7         8

5.1      4.7      4.3      4.6      4.6       4.8      4.9      4.3

4.4      4.5      4.6      4.4      4.3       4.3      5.1      4.8

4.7      4.9      4.4      5         4.7       4.8      4.5      5

4.9      5.1      4.6      4.9      5          5         4.6      4.7

4.9       5.2       4.9       4.7       4.7       4.3       4.7       5.2