Editing Coefficient of variation (section)

{{Short description|Statistical parameter}}
{{distinguish|Coefficient of determination}}
{{Use American English|date=January 2019}}
{{Use dmy dates|date=October 2017}}

In [[probability theory]] and [[statistics]], the '''coefficient of variation''' ('''CV'''), also known as normalized [[Root-mean-square deviation|root-mean-square deviation]] (NRMSD), '''percent RMS''', and '''relative standard deviation''' ('''RSD'''), is a [[Standardized (statistics)|standardized]] measure of [[statistical dispersion|dispersion]] of a [[probability distribution]] or [[frequency distribution]]. It is defined as the ratio of the [[standard deviation]] <math> \sigma </math> to the [[mean]] <math> \mu </math> (or its [[absolute value]], {{nowrap|<math>| \mu |</math>)}}, and often expressed as a percentage ("%RSD"). The CV or RSD is widely used in [[analytical chemistry]] to express the precision and repeatability of an [[assay]]. It is also commonly used in fields such as [[engineering]] or [[physics]] when doing quality assurance studies and [[ANOVA gauge R&R]],{{citation needed|date=September 2016}} by economists and investors in [[economic model]]s, in [[epidemiology]], and in [[psychology]]/[[neuroscience]].