Recall that one group of students was given a completed homework solution and another group was given only check figures at various steps of the solution. The researchers wanted to compare the average test score improvement of the two groups. How many students should be sampled in each group to estimate the difference in the averages to within .5 point with 99% confidence? Assume that the standard deviations of the test score improvements for the two groups are approximately equal to 1.
For Information: Refer to the Journal of Accounting Education (Vol. 25, 2007) study of providing homework assistance to accounting students. Exercise 8.18.