statsmodels.sandbox.stats.runs.symmetry_bowker

statsmodels.sandbox.stats.runs.symmetry_bowker(table)

Test for symmetry of a (k, k) square contingency table

This is an extension of the McNemar test to test the Null hypothesis that the contingency table is symmetric around the main diagonal, that is

n_{i, j} = n_{j, i} for all i, j

Parameters:table (array_like, 2d, (k, k)) – a square contingency table that contains the count for k categories in rows and columns. Returns:

• statistic (float) – chisquare test statistic
• p-value (float) – p-value of the test statistic based on chisquare distribution
• df (int) – degrees of freedom of the chisquare distribution

Notes

Implementation is based on the SAS documentation, R includes it in mcnemar.test if the table is not 2 by 2.

The pvalue is based on the chisquare distribution which requires that the sample size is not very small to be a good approximation of the true distribution. For 2x2 contingency tables exact distribution can be obtained with mcnemar

See also

mcnemar