For a given item the upper specification limit is 60 and the lower specification limit is 37. It can be assumed that: 1) the process mean is centered in the specification interval; and 2) the process standard deviation is 2.3. What is this process’ capability ratio?
Expert Answer
As USL = 60
LSL = 37
S= Sigma = Std Dev =2.3
Hence process capability ration = CP index= (UCL – LCL)/6S = 23/(6*2.3) = 10/6 =1.667