Seyed Sina Jalali - Azad University South Tehran Branch;

Element of quality with a certain numbers of uses in applicable statistics and is attracting growing carefulness in quality control is the coefficient of variation (CV).One of the most important concepts of statistical process control is that a normally distributed process is not able to be said to be in control unless it has a continuous mean and variance. It means that a change in the mean and/or the standard deviation renders the process out of control. Control charting methods however, have newly been expanded to different sections where the mean and standard deviation might not be persistent entire of the time, but the process 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, (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. Comparing the marginal CVs can lead to contradictions in the multivariate environment, that is, when the collation of relative variability is based on some features. Therefore in numerous articles and implementations, the use of MCV summarizing the relative dispersion in one sole index which has already been advocated.

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