Talk:Process performance index

Hello...noticing that the Process Performance article is not entirely accurate as the Process Performance Index is calculated using the standard deviation for the process and not the sample standard deviation. Also, the Ppk is more of a long-term measure and the text seems to indicate that it is not. The description here seems to more closely match the Process Capability Index or Cpk. 99.162.81.250 (talk) 00:08, 25 March 2019 (UTC)