A normally distributed process has specifications of LSL = 75 and USL = 85 on the output.

Question:

A normally distributed process has specifications of LSL = 75 and USL = 85 on the output. A random sample of 25 parts indicates that the process is centered at the middle of the specification band, and the standard deviation is s = 1.5.
(a) Find a point estimate of Cp.
(b) Find a 95% confidence interval on Cp. Comment on the width of the interval.