This paper compares between two multivariate procedures performance: The first procedure based on Hotelling's T2 quality control chart which is process variability and methods that address which variable (s) caused the out-of-control signal. While the second procedure is generalized variance |S| quality control chart which is very powerful way to detect small shifts in the mean vector. Generalized variance |S| is allowing us to simultaneously monitor whether two or more related variables are in control, and it is shown that multivariate quality control chart do not indicate which variables cause the out-of-control signal so that the interpretation of the out-of-control signal. The compare was showed a control chart commonly requires samples with fixed size be taken at fixed intervals and assumed that in both univariate and multivariate control charts, each sample is independent of the previous samples. In addition, this paper compares between Hotelling's T2 quality control chart and generalized variance |S| control chart procedures by application with real data. |
