Calculate the value of cpknbspfor each of the

Question

If a process variable is normally distributed, in the long run virtually all observed values should be between 

a. With LSL and USL denoting the lower and upper specification limits, one commonly used process capability index is 

 C_p = 1 indicates a process that is only marginally capable of meeting specifications. Ideally, C_p should exceed 1.33 (a  "very good" process). Calculate the value of C_p for each of the cork production processes described in the previous exercise, and comment. b. The C_p index described in (a) does not take into account process location. A capability measure that does involve the process mean is

Calculate the value of C_pk for each of the corkproduction processes described in the previous exercise, and comment. 
c. How do C_p and C_pk compare, and when are they equal?