What is the power of a test?
The probability of rejecting H0H_0H0 when H0H_0H0 is true.
The probability of failing to reject H0H_0H0 when H0H_0H0 is false.
The probability of rejecting H0H_0H0 when H0H_0H0 is false (1−β1 - \beta1−β).
The same as the significance level α\alphaα.