Chapter 9.2, Problem 5Q

The University of Missouri–St. Louis gave a validation test to entering students who had taken calculus in high school. The group of ninety-three students receiving no college credit had a mean score of 4.17 on the validation test with a sample standard deviation of 3.70. For the twenty-eight students who received credit from a high school dual-enrollment class, the mean score was 4.61 with a sample standard deviation of 4.28. Is there a significant difference in these means at the $\alpha =0.01$ level? Assume the variances are equal.

Data from: MAA Focus, December 2008, p. 19.