statsmodels.stats.proportion.power_proportions_2indep#
- statsmodels.stats.proportion.power_proportions_2indep(diff, prop2, nobs1, ratio=1, alpha=0.05, value=0, alternative='two-sided', return_results=True)[source]#
Power for ztest that two independent proportions are equal
This assumes that the variance is based on the pooled proportion under the null and the non-pooled variance under the alternative
- Parameters:
- diff
float difference between proportion 1 and 2 under the alternative
- prop2
float proportion for the reference case, prop2, proportions for the first case will be computed using p2 and diff p1 = p2 + diff
- nobs1
floatorint number of observations in sample 1
- ratio
float,optional sample size ratio, nobs2 = ratio * nobs1
- alpha
floatininterval(0,1),optional Significance level, e.g., 0.05, is the probability of a type I error, that is wrong rejections if the Null Hypothesis is true.
- value
float,optional currently only value=0, i.e., equality testing, is supported
- alternative{‘two-sided’, ‘larger’, ‘smaller’},
optional Alternative hypothesis whether the power is calculated for a two-sided (default) or one sided test. The one-sided test can be either ‘larger’, ‘smaller’.
- return_resultsbool,
optional If true, then a results instance with extra information is returned, otherwise only the computed power is returned.
- diff
- Returns:
PowerProportionsResultorfloatIf return_results is True (default), then a
PowerProportionsResultnamedtuple is returned. If return_results is False, then only the power is returned as a float.