Seyed Sina Jalali - Faculty of Industrial Engineering, Azad University, South Tehran Branch

Element of quality with a certain numbers of uses in applicable statistics is coefficient of variation (CV).One of the vital concepts of operation control in terms of statistic is that an operation with normal distribution can not be said to be in control unless it has a continuous mean (ʽ) and variance ( ۲). It means that a change in the ʽ and/or the standard deviation ( ) renders the operation out of control. Methods related to control charts:however, have newly been expanded to different sections where ʽ and might not be persistent entire of the time, nevertheless the operation is in control.In this instance, the utilization of the CV is obviously to be investigated. Universally, it is commonly utilized to contrast data groups of various units or means that are widely different. Besides, the CV has many implementations in the business. In addition to the CV,multivariate coefficient of variation (MCV) can be utilized to conveniently compare multiple populations based on more than one property, as they allow relative dispersion to be summarized in a single index. Contrasting the marginal CVs can conduct to conflict in the multivariate environment, that is, when the collation of corresponding variability is relied on some features. Therefore in numerous articles and implementations, the use of MCV abstracting the corresponding dispersion in one sole index has being recommended so far.In this paper,a detailed review on CV and multivariate one has been considered in order to lead quality practitioners to novel relevant researches in these scopes.

CV, MCV,CV quality chart,MCV quality chart,quality control charts performance indices.