A researcher is investigating the effectiveness of a new medication for lowering blood pressure for individuals with systolic pressure greater than 140.
For this population, systolic scores average µ = 160 with a standard deviation of s = 20, and the scores form a normal-shaped distribution. The researcher plans to select a sample of n = 25 individuals, and measure their systolic blood pressure after they take the medication for 60 days. If the researcher uses a two-tailed test with a = .05,
a. What is the power of the test if the medication has a 5-point effect?
b. What is the power of the test if the medication has a 10-point effect?