Graphical Analysis of Process Variation Studies

Summary: Graphical procedures for analyzing the results of nested sampling studies are presented and illustrated with examples. It is shown that a standard deviation control chart analysis will detect atypical results and nonhomogeneous variances that can greatly distort the estimated process variance components. The procedure enables the quality engineer to see the sources and magnitude of the variation in the process and to identify any unusual characteristics of the data. This information can provide a basis for improving product quality.