7.90 Comparison of packaging plants: power.

Exercise 7.55 (page 395) summarizes data on the number of seeds in one-pound scoops from two different packaging plants. Suppose that you are designing a new study for their next improvement effort. Based on information from the company, you want to identify a difference in these plants of 150 seeds. For planning purposes assume that you will have 20 scoops from each plant and that the common standard deviation is 190 seeds, a guess that is roughly the pooled sample standard deviation. If you use a pooled two-sample test with significance level 0.05, what is the power of the test for this design?