<P> In probability theory and statistics, the coefficient of variation (CV), also known as relative standard deviation (RSD), is a standardized measure of dispersion of a probability distribution or frequency distribution . It is often expressed as a percentage, and is defined as the ratio of the standard deviation σ (\ displaystyle \ \ sigma) to the mean μ (\ displaystyle \ \ mu) (or its absolute value, μ (\ displaystyle \ mu)). 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 . In addition, CV is utilized by economists and investors in economic models and in determining the volatility of a security . </P> <P> The coefficient of variation (CV) is defined as the ratio of the standard deviation σ (\ displaystyle \ \ sigma) to the mean μ (\ displaystyle \ \ mu): c v = σ μ . (\ displaystyle c_ (\ rm (v)) = (\ frac (\ sigma) (\ mu)).) It shows the extent of variability in relation to the mean of the population . The coefficient of variation should be computed only for data measured on a ratio scale, as these are the measurements that allow the division operation . The coefficient of variation may not have any meaning for data on an interval scale . For example, most temperature scales (e.g., Celsius, Fahrenheit etc .) are interval scales with arbitrary zeros, so the coefficient of variation would be different depending on which scale you used . On the other hand, Kelvin temperature has a meaningful zero, the complete absence of thermal energy, and thus is a ratio scale . While the standard deviation (SD) can be meaningfully derived using Kelvin, Celsius, or Fahrenheit, the CV is only valid as a measure of relative variability for the Kelvin scale because its computation involves division . </P> <P> Measurements that are log - normally distributed exhibit stationary CV; in contrast, SD varies depending upon the expected value of measurements . </P>

What is the formula of coefficient of variation
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