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

confidence interval for the difference in means

  • 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

lower, upper – lower and upper limits of the confidence interval

Return type:



The result is independent of the user specified ddof.

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© 2006–2008 Scipy Developers
© 2006 Jonathan E. Taylor
Licensed under the 3-clause BSD License.