E Hargrove replied to the topic Any one could tell me when I should use CPK or PPK? THKS! in the forum General 18 years, 11 months ago
Under “ideal” conditions the result of Cpk and Ppk should be the same. Ideal conditions being: normal distribution, sufficient data set size, non-autocorrelated data, data in statistical control.
Strictly speaking the use of moving range is an inferential for standard deviation. Anything that would cause moving range / d2 to deviate from th…[Read more]