statsmodels.stats.weightstats._tstat_generic

statsmodels.stats.weightstats._tstat_generic(value1, value2, std_diff, dof, alternative, diff=0)[source]

generic ttest based on summary statistic

The test statistic is :

tstat = (value1 - value2 - diff) / std_diff

and is assumed to be t-distributed with dof degrees of freedom.

Parameters:

  • value1 (float or ndarray) – Value, for example mean, of the first sample.

  • value2 (float or ndarray) – Value, for example mean, of the second sample.

  • std_diff (float or ndarray) – Standard error of the difference value1 - value2

  • dof (int or float) – Degrees of freedom

  • alternative (str) –

    The alternative hypothesis, H1, has to be one of the following

    • ’two-sided’ : H1: value1 - value2 - diff not equal to 0.

    • ’larger’ : H1: value1 - value2 - diff > 0

    • ’smaller’ : H1: value1 - value2 - diff < 0

  • diff (float) – value of difference value1 - value2 under the null hypothesis

Returns:

  • tstat (float or ndarray) – Test statistic.

  • pvalue (float or ndarray) – P-value of the hypothesis test assuming that the test statistic is t-distributed with df degrees of freedom.