Control charts for the coefficient of variation

Abstract

The subject of this essay is the investigation and presentation of control charts for the coefficient of variation CV. We investigated and presented a sufficient number of control charts that have been proposed during the last ten years. Some of those are simple, other use specific techniques in order to more efficiently detect changes in the CV. In some control charts calculations were extended in order to have more values that cover sample size, the coefficient of variation and its changes. For data derived from simulations we combined some control charts and compared them for different changes in the CV.