scipy.stats.variation

scipy.stats.variation(a, axis=0, nan_policy='propagate')

Compute the coefficient of variation.

The coefficient of variation is the ratio of the biased standard deviation to the mean.

Parameters

aarray_like

Input array.

axisint or None, optional

Axis along which to calculate the coefficient of variation. Default is 0. If None, compute over the whole array a.

nan_policy{‘propagate’, ‘raise’, ‘omit’}, optional

Defines how to handle when input contains nan. The following options are available (default is ‘propagate’):

• ‘propagate’: returns nan

• ‘raise’: throws an error

• ‘omit’: performs the calculations ignoring nan values

Returns

variationndarray

The calculated variation along the requested axis.

References

1

Zwillinger, D. and Kokoska, S. (2000). CRC Standard Probability and Statistics Tables and Formulae. Chapman & Hall: New York. 2000.

Examples

>>> from scipy.stats import variation
>>> variation([1, 2, 3, 4, 5])
0.47140452079103173