SciPy

scipy.stats.ttest_ind_from_stats

scipy.stats.ttest_ind_from_stats(mean1, std1, nobs1, mean2, std2, nobs2, equal_var=True)[source]

T-test for means of two independent samples from descriptive statistics.

This is a two-sided test for the null hypothesis that 2 independent samples have identical average (expected) values.

Parameters:

mean1 : array_like

The mean(s) of sample 1.

std1 : array_like

The standard deviation(s) of sample 1.

nobs1 : array_like

The number(s) of observations of sample 1.

mean2 : array_like

The mean(s) of sample 2

std2 : array_like

The standard deviations(s) of sample 2.

nobs2 : array_like

The number(s) of observations of sample 2.

equal_var : bool, optional

If True (default), perform a standard independent 2 sample test that assumes equal population variances [R448]. If False, perform Welch’s t-test, which does not assume equal population variance [R449].

Returns:

statistic : float or array

The calculated t-statistics

pvalue : float or array

The two-tailed p-value.

Notes

New in version 0.16.0.

References

[R448](1, 2) http://en.wikipedia.org/wiki/T-test#Independent_two-sample_t-test
[R449](1, 2) http://en.wikipedia.org/wiki/Welch%27s_t_test

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