- Examine the power curves. There are three curves, one for the 0.01, one
for the 0.05, and one for the 0.10 significance level. The X axis shows sample
size, the Y axis shows power. Note the effect of sample size and significance
level on power.
- The default difference between the population mean and hypothesized mean
is 1.55. Use the slider to change this value and note the effect on the power
curves.
- Change the population standard deviation (sd) and notice its effect on
power.
- Compare the power of one-tailed and two-tailed tests when the difference
between the population mean and hypothesized mean is 2. Determine which
is higher.
- Set the difference between the population mean and hypothesized mean to
zero. Since the null hypothetsis is true, the Y axis no shows the Type I
error rate, not power. Note the effect of sample size on the Type I error
rate.
- Determine the effect of changing the standard deviation on the Type I error
rate.