Computes the coefficient of variation, the ratio of the biased standard deviation to the mean.
| Parameters : | a : array_like 
 axis : int or None 
 | 
|---|
References
| [R203] | Zwillinger, D. and Kokoska, S. (2000). CRC Standard Probability and Statistics Tables and Formulae. Chapman & Hall: New York. 2000. |