Software can generate samples from (almost) exactly Normal distributions.
Here is a random sample of size 5 from the Normal distribution with mean 10 and standard deviation 2:
6.47 7.51 10.10 13.63 9.91
These data match the conditions for a z test better than real data will: the population is very close to Normal and has known standard deviation s = 2, and the population mean is µ = 10.
Test the hypotheses
H0 : µ = 8
Ha : µ ? 8
In Exercise 15.41 (given above), a sample from a Normal population with mean µ = 10 and standard deviation s = 2 failed to reject the null hypothesis H0 : µ = 8 at the a = 0.05 significance level.
Enter the information from this example into the Power of a Test applet.
(Don't forget that the alternative hypothesis is two-sided.)
What is the power of the test against the alternative µ = 10?
