Question: An educational psychologist studies the effect of frequent testing on retention of

course material. In one of the professor’s sections, students are given quizzes each week. The second section receives only two tests during the semester. At the end of the semester, both sections receive the same cumulative final exam. Data is provided below.

(a) Is there a significant effect of testing frequency on retention? Use the .01 level of significance.

(b) Construct the 90% confidence interval for the population mean differences.

Frequent Quizzes Two Exams

SS = 175 SS = 145