Seven samples of 5 parts each have been collected from an extrusion process that is in statistical control, and the diameter of the extrudate has been measured for each part. The calculated values of x for each sample are (in) 1.002, 0.999, 0.995, 1.004, 0.996, 0.998, and 1.006. The values of R are (in) 0.010, 0.011, 0.014, 0.020, 0.008, 0.013, and 0.017, respectively.
(a) Determine the values of the center, LCL, and UCL for and R charts.
(b) Construct the control charts and plot the sample data on the charts.