A biologist hypothesizes that the mean life expectancy of a fly is 10.5 days. Researchers believe the true mean is more than 10.5 days and they plan a hypothesis test at the 5% significance level on a random sample of 70 of these flies. If the alternative hypothesis is correct, for which of the following values of μ is the power of the test greatest?
μ = 9
μ = 10.5
μ = 19
μ = 20
μ = 21
