Monitoring Coefficient of Variation Using Progressive Mean Technique

Abstract

Control charts are mostly used for the monitoring of process mean and dispersion. In cases, when the process standard deviation is proportional to the mean, it is recommended to use control charts based on coefficient of variation (CV). In this study, a new control chart, namely the CVPMchart, is proposed for the monitoring of process CV using the progressive mean statistic. The performance of the CVPMchart is evaluated using average run length, standard deviation of run length, median run length, extra quadratic loss and relative average run length measures. The run length comparison indicated better detection ability of the CVPMchart as compared to other competing CV charts. A real-life example is also provided to show the illustration of the proposed chart. The study will help quality practitioners to choose an efficient control chart for the monitoring of process CV.