Now, we will consider the impact of using a different alpha value.
4. Alpha level: For this example, use one-tailed alpha = .01 (z = 2.326). In this case, we will reject the null hypothesis only if a sample mean is so large that it would occur less than 1% of the time given the null hypothesis is true. You do not need to draw additional samples for this problem; you can use the data recorded for samples drawn in Sampling Exercise 1. You will need to use the applet to calculate power for the tests using alpha = .01.
Using these criteria, how many times could you reject the null hypothesis for your results in Problem #1?
| alpha = .05 (from #1) | alpha = .01 | |
| Reject for Program A (alternative mean = 667) |
_______ | _______ |
| Reject for Program C (alternative mean = 585) |
_______ | _______ |
Using these criteria, what is the power for each of these tests?
| alpha = .05 (from #1) | alpha = .01 | |
| Power for Program A (alternative mean = 667) |
_______ | _______ |
| Power for Program C (alternative mean = 585) |
_______ | _______ |
Does power rise or fall using alpha = .01 compared to .05? Why?
Go to WISE Power applet (Go to the applet to get values for power)