TTestPower.power()

statsmodels.stats.power.TTestPower.power

TTestPower.power(effect_size, nobs, alpha, df=None, alternative='two-sided') [source]

Calculate the power of a t-test for one sample or paired samples.

Parameters:

effect_size : float standardized effect size, mean divided by the standard deviation. effect size has to be positive. nobs : int or float sample size, number of observations. alpha : float in interval (0,1) significance level, e.g. 0.05, is the probability of a type I error, that is wrong rejections if the Null Hypothesis is true. df : int or float degrees of freedom. By default this is None, and the df from the one sample or paired ttest is used, df = nobs1 - 1 alternative : string, ?two-sided? (default), ?larger?, ?smaller? extra argument to choose whether the power is calculated for a two-sided (default) or one sided test. The one-sided test can be either ?larger?, ?smaller?. .

Returns:

power : float Power of the test, e.g. 0.8, is one minus the probability of a type II error. Power is the probability that the test correctly rejects the Null Hypothesis if the Alternative Hypothesis is true.