Figure 12-B contains data from a process that produces holes (drilling) with limits of 6.00 to 6.70 mm. The control charts for  and R using n = 5 and k = 25 are shown in the figure, also. (The numbers in the body of the table are 6.47, 6.19, 6.19,6.29, etc.)
a. Using the data for n = 5, k = 25, develop the process capability indexes Cp and Cpk, and discuss the capability of this process.
b. Using the data n = 5, k = 25, develop the σ control chart and use  to estimate σ′ for the process capability indexes Cp and Cpk.
c. Develop , R, and σ charts for samples sizes of 4 or 3 by ignoring X5 or X3 and X5 (or any combination of individual values). Use the charts to perform a process capability study.