Exclusive Content & Downloads from ASQ

The Effect of Pooled and Un-pooled Variance Estimators of C(pm) When Using Subsamples

Summary: [This abstract is based on the authors' abstract.] In actual manufacturing practice, subsamples representing logical subgroups, rather than a single representative sample, are typically collected over time for the purpose of quality control. In light of this more realistic data structure, two C(pm) estimators corresponding to pooled and un-pooled variance estimators are evaluated and applied to hypothesis testing and power calculations. Power functions of these tests are used to determine the minimum number of subsamples needed. Tables provide recommended numbers and usage of subsamples.

Anyone with a subscription, including Site and Enterprise members, can access this article.

Other Ways to Access content:

Join ASQ

Join ASQ as a Full member. Enjoy all the ASQ member benefits including access to many online articles.

Subscribe to Journal of Quality Technology

Access this and ALL OTHER Journal of Quality Technology online articles. You'll also receive the print version by mail.

  • Topics: Process Capability, Sampling
  • Keywords: Multivariate capability indices,Hypothesis testing,Process capability (Cp),Sample estimates,Sample size
  • Author: Hubele, Norma Faris; Vannman, Kerstin
  • Journal: Journal of Quality Technology