Power of a test

The power of a test is the probability that a test will reject a false null hypothesis. (= 1–Prob(Type II Error)). In the graph of hypothesized and actual distributions below the power of a right tailed test is represented by the green shaded area. Move the sliders to see how (i) difference between hypothesized and actual means (ii) standard error (which is smaller for larger samples) (iii) alpha level affect the power of the test