Abstract
Recent studies have shown that the T 2 control chart with variable sampling intervals (VSI) and/or variable sample sizes (VSS) detects process shifts faster than the traditional T 2 chart. This article extends these studies for processes that are monitored with VSI and VSS using double warning lines (T 2 -DWL). It is assumed that the length of time the process remains in control has exponential distribution. The properties of T 2 -DWL chart are obtained using Markov chains. The results show that the T 2 -DWL chart is quicker than VSI and/or VSS charts in detecting almost all shifts in the process mean.
| Original language | English |
|---|---|
| Pages (from-to) | 569-593 |
| Number of pages | 25 |
| Journal | Statistical Papers |
| Volume | 47 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - Oct 2006 |
Keywords
- Double Warning Lines Scheme
- Markov chain process
- Multivariate T control chart
- Multivariate quality control
- Variable sampling plan