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fligner(*samples, center='median', proportiontocut=0.05)

Fligner's test tests the null hypothesis that all input samples are from populations with equal variances. Fligner-Killeen's test is distribution free when populations are identical .

Notes

As with Levene's test there are three variants of Fligner's test that differ by the measure of central tendency used in the test. See levene for more information.

Conover et al. (1981) examine many of the existing parametric and nonparametric tests by extensive simulations and they conclude that the tests proposed by Fligner and Killeen (1976) and Levene (1960) appear to be superior in terms of robustness of departures from normality and power .

Parameters

sample1, sample2, ... : array_like: Arrays of sample data. Need not be the same length.
center : {'mean', 'median', 'trimmed'}, optional: Keyword argument controlling which function of the data is used in computing the test statistic. The default is 'median'.
proportiontocut : float, optional: When center is 'trimmed', this gives the proportion of data points to cut from each end. (See scipy.stats.trim_mean.) Default is 0.05.

Returns

statistic : float: The test statistic.
pvalue : float: The p-value for the hypothesis test.

Perform Fligner-Killeen test for equality of variance.

Examples

Test whether or not the lists `a`, `b` and `c` come from populations with equal variances.

import numpy as np
from scipy.stats import fligner
a = [8.88, 9.12, 9.04, 8.98, 9.00, 9.08, 9.01, 8.85, 9.06, 8.99]
b = [8.88, 8.95, 9.29, 9.44, 9.15, 9.58, 8.36, 9.18, 8.67, 9.05]
c = [8.95, 9.12, 8.95, 8.85, 9.03, 8.84, 9.07, 8.98, 8.86, 8.98]
stat, p = fligner(a, b, c)
p

The small p-value suggests that the populations do not have equal variances.

This is not surprising, given that the sample variance of `b` is much larger than that of `a` and `c`:

[np.var(x, ddof=1) for x in [a, b, c]]

See :

Back References

The following pages refer to to this document either explicitly or contain code examples using this.

scipy.stats._morestats:bartlett scipy.stats._morestats:ansari scipy.stats._morestats:mood

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