CompareMeans.zconfint_diff()

statsmodels.stats.weightstats.CompareMeans.zconfint_diff

CompareMeans.zconfint_diff(alpha=0.05, alternative='two-sided', usevar='pooled') [source]

confidence interval for the difference in means

Parameters:

alpha : float significance level for the confidence interval, coverage is 1-alpha alternative : string This specifies the alternative hypothesis for the test that corresponds to the confidence interval. The alternative hypothesis, H1, has to be one of the following : ?two-sided?: H1: difference in means not equal to value (default) ?larger? : H1: difference in means larger than value ?smaller? : H1: difference in means smaller than value usevar : string, ?pooled? or ?unequal? If pooled, then the standard deviation of the samples is assumed to be the same. If unequal, then Welsh ttest with Satterthwait degrees of freedom is used

Returns:

lower, upper : floats lower and upper limits of the confidence interval

Notes

The result is independent of the user specified ddof.