A double sampling multivariate T2 control chart with variable sample size and variable sampling interval.

This paper presents an adaptive T2 control chart for monitoring shifts in the mean vector of a multivariate normally distributed process. This chart which combines the double sampling, variable sample size and variable sampling interval features, called the DSVSSI T2 chart and uses three different sample sizes, two different sampling intervals, two warning limits and two different control limits. A Markov chain approach is employed to compute the statistical performance measures. The proposed chart is compared with the existing standard T2 and other adaptive multivariate T2 charts. In all cases, the DSVSSI T2 chart is quicker at detecting small to moderate shifts in the mean vector. An example is provided to illustrate the construction and implementation of the DSVSSI T2 chart. Finally, some concluding remarks are given. [ABSTRACT FROM AUTHOR]