statsmodels.stats.weightstats.ttest_ind¶
-
statsmodels.stats.weightstats.
ttest_ind
(x1, x2, alternative='two-sided', usevar='pooled', weights=(None, None), value=0)[source]¶ ttest independent sample
Convenience function that uses the classes and throws away the intermediate results, compared to scipy stats: drops axis option, adds alternative, usevar, and weights option.
Parameters: x1 : array_like, 1-D or 2-D
first of the two independent samples, see notes for 2-D case
x2 : array_like, 1-D or 2-D
second of the two independent samples, see notes for 2-D case
alternative : str
The alternative hypothesis, H1, has to be one of the following
- ‘two-sided’ (default): H1: difference in means not equal to value
- ‘larger’ : H1: difference in means larger than value
- ‘smaller’ : H1: difference in means smaller than value
usevar : str, ‘pooled’ or ‘unequal’
If
pooled
, then the standard deviation of the samples is assumed to be the same. Ifunequal
, then Welsh ttest with Satterthwait degrees of freedom is usedweights : tuple of None or ndarrays
Case weights for the two samples. For details on weights see
DescrStatsW
value : float
difference between the means under the Null hypothesis.
Returns: tstat : float
test statistic
pvalue : float
pvalue of the t-test
df : int or float
degrees of freedom used in the t-test