statsmodels.stats.weightstats.ttost_ind¶
- statsmodels.stats.weightstats.ttost_ind(x1, x2, low, upp, usevar='pooled', weights=(None, None), transform=None)[source]¶
test of (non-)equivalence for two independent samples
TOST: two one-sided t tests
null hypothesis: m1 - m2 < low or m1 - m2 > upp alternative hypothesis: low < m1 - m2 < upp
where m1, m2 are the means, expected values of the two samples.
If the pvalue is smaller than a threshold, say 0.05, then we reject the hypothesis that the difference between the two samples is larger than the the thresholds given by low and upp.
- Parameters
- x1array_like, 1-D or 2-D
first of the two independent samples, see notes for 2-D case
- x2array_like, 1-D or 2-D
second of the two independent samples, see notes for 2-D case
- low, upp
float
equivalence interval low < m1 - m2 < upp
- 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 used- weights
tuple
of
None
orndarrays
Case weights for the two samples. For details on weights see
DescrStatsW
- transform
None
orfunction
If None (default), then the data is not transformed. Given a function, sample data and thresholds are transformed. If transform is log, then the equivalence interval is in ratio: low < m1 / m2 < upp
- Returns
Notes
The test rejects if the 2*alpha confidence interval for the difference is contained in the
(low, upp)
interval.This test works also for multi-endpoint comparisons: If d1 and d2 have the same number of columns, then each column of the data in d1 is compared with the corresponding column in d2. This is the same as comparing each of the corresponding columns separately. Currently no multi-comparison correction is used. The raw p-values reported here can be correction with the functions in
multitest
.