A Synthetic Scaled Weighted Variance Control Chart for Monitoring the Process Mean of Skewed Populations

Abstract

In this article, a synthetic scaled weighted variance (synthetic SWV-) control chart is proposed to monitor the process mean of skewed populations. This control chart is an improvement over the synthetic weighted variance (synthetic WV-) chart suggested by Khoo et al. (2008), in the detection of a negative shift in the mean. A comparison between the performances of the synthetic SWV- and synthetic WV- charts are made in terms of the average run length (ARL) values for the various levels of skewnesses as well as different magnitudes of positive and negative shifts in the mean. A method to construct the synthetic SWV- chart is explained in detail. An illustrative example is also given to show the implementation of the synthetic SWV- chart.

Keywords:

• Johnson distributions
• Scaled weighted variance X¯ chart
• Synthetic X¯ chart
• Weighted variance X¯ chart

Mathematics Subject Classification:

• 62P30
• 62E17