Coefficient of Variation Calculator
Compare variability relative to the mean.
Coefficient of variation formula
CV = standard deviation / |mean| × 100%. It is useful for comparing relative dispersion across datasets with different scales.
Understanding Coefficient of Variation
The coefficient of variation expresses standard deviation as a percentage of the mean. It is useful for comparing relative variability between data sets that have different scales or units.
Coefficient of Variation Example
If a data set has a mean of 50 and a standard deviation of 5, the coefficient of variation is 10%. A second data set with a different unit can be compared on the same relative basis when its mean is not close to zero.
When CV Is Most Useful
CV works best with ratio-scale measurements and positive means. Values can become misleading when the mean is near zero or when the data naturally include negative values.
Frequently Asked Questions
Is a lower CV always better?
Not necessarily. A lower CV simply indicates less variability relative to the mean.
Can CV exceed 100%?
Yes. That can happen when the standard deviation is larger than the mean.
Why use CV instead of standard deviation?
CV makes variability easier to compare across different scales.
When Coefficient of Variation Is Useful
The coefficient of variation expresses standard deviation relative to the mean, making it useful for comparing relative variability across positive ratio-scale measurements with different units or magnitudes. It becomes unstable when the mean is near zero and is generally inappropriate when zero is arbitrary.
Methodology, Assumptions and Interpretation
Coefficient of variation is standard deviation divided by mean, usually expressed as a percentage. It is most interpretable for ratio-scale data with a meaningful zero and can become unstable or misleading when the mean is near zero or negative.