statsmodels.stats.weightstats.CompareMeans.ttest_ind¶
-
CompareMeans.
ttest_ind
(alternative='two-sided', usevar='pooled', value=0)[source]¶ ttest for the null hypothesis of identical means
this should also be the same as onewaygls, except for ddof differences
- 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’: 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 : 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 usedvalue : 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
Notes
The result is independent of the user specified ddof.