In this article, we propose the S chart with variable charting statistic to control the covariance matrix as an alternative to the use of the bivariate |S| chart and the trivariate VMAX chart. As usual, samples are regularly ...

Recent theoretical studies have shown that the X̄ chart with variable sampling intervals (VSI) and the X̄ chart with variable sample size (VSS) are quicker than the traditional X̄ chart in detecting shifts in the process. ...

Recent theoretical studies have shown that the X̄ chart with variable sampling intervals (VSI) and the X̄ chart with variable sample size (VSS) are quicker than the traditional X̄ chart in detecting shifts in the process. ...

This article proposes two Shewhart charts, denoted np(xy) and np(w) charts, which use attribute inspection to control the mean vector ((x); (y)) of bivariate processes. The units of the sample are classified as first-class, ...

Theoretical results have shown that the X̄ chart with variable sample sizes (VSS) is quicker than the traditional X̄ chart for detecting moderate shifts in the process. The idea is to make the sample size vary depending ...

Varying the parameters of the X̄ chart has been explored extensively in recent years. In this paper, we extend the study of the X̄ chart with variable parameters to include variable action limits. The action limits establish ...

Varying the parameters of the X̄ chart has been explored extensively in recent years. In this paper, we extend the study of the X̄ chart with variable parameters to include variable action limits. The action limits establish ...