The Use of R and S2 Charts Under Nonstandard Conditions.
Abstract
R and S-squared charts for monitoring the variability of a process are studied when the control variance, (sigma sub 0) squared is unknown, when observations are non-Gaussian, and when the process drifts. Geometric bounds on run-length distributions for the R and S-squared charts are given for all underlying distributions when (sigma sub 0) squared is estimated in a base period. Similar bounds apply in the case of a drifting process, the notion of which is developed rigorously. It is shown that normal-theory properties of these charts hold exactly for every spherical process when a suitable estimate for (sigma sub 0) squared is used. Run-length distributions otherwise are shown to be ordered stochastically given a peakedness ordering on the underlying spherical processes. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1980
- Accession Number
- ADA083032
Entities
People
- D. R. Jensen
- Y. V. Hui
Organizations
- Virginia Tech