Examining Power and Error in Tests of Significance

Dan Ross
Explore the concepts of power and error in tests of significance. Sampling distributions of sample means are shown for the hypothesized mean (in red) and the actual mean (in blue). The area of rejection of the null hypothesis can be adjusted, and the actual probability of rejecting the null hypothesis (based on the real mean) is shown in gray and it's value is shown as the number p.
Can you determine:
  1. What area corresponds to the power of the test?
  2. What area corresponds to a Type I error?
  3. What area corresponds to a Type II error?