Students can explore power and error for one-tailed tests of significance (assuming the sampling distribution of sample means is normally distributed) by comparing the sampling distribution based on the hypothesized mean, the sampling distribution based on the real mean, and the area of rejection for the null hypothesis.
Sliders allow changing the hypothesized and real means, the area of rejection, and standard deviation of the sampling distributions.
Students are asked to consider what areas correspond to power and Type I and II errors.