$\bar{X}$ CONTROL CHART FOR SKEWED POPULATIONS USING A SCALED WEIGHTED VARIANCE METHOD

Abstract

This paper proposes a new [Formula: see text] control chart devoted to the monitoring of skewed populations. This control chart, called the Scaled Weighted Variance[Formula: see text] control chart (SWV [Formula: see text] for short), is an improvement of the Weighted Variance [Formula: see text] control chart proposed by Choobineh and Ballard in 1987. In this paper we derive the control limits of the SWV [Formula: see text] control chart and give an illustrative example. Comparisons in terms of type I error and ARL are performed in the case of a lognormal, gamma and Weibull population.