A researcher is evaluating the influence of a treatment using a sample selected from a normally distributed population with a mean of µ = 80 and a standard deviation of s = 20. The researcher expects a 12-point treatment effect and plans to use a two-tailed hypothesis test with a = .05.
a. Compute the power of the test if the researcher uses a sample of n = 16 individuals.
b. Compute the power of the test if the researcher uses a sample of n = 25 individuals.