Question

On its website, the Kaplan Prep claims that students who have taken its course improve their GRE scores, on average, by 210 points. (No other information is provided about this statistic.) Treating this average gain as a population mean, a researcher wonders whether the far cheaper technique of practicing for the GRE on one’s own using books and CDs will lead to a different average gain. She randomly selects nine students from the pool of students at her university who plan to take the GRE. The students take a practice test before and after 2 months of study. They report gains of 260, 240, 340, 170, 250, 230, 250, 220, and 250 points. Are gains in GRE scores from taking the Kaplan Prep course different from GRE gains when studying using books and CDs? Assume an alpha level of .05. a. What type of t-test will you use to answer this question? Why did you choose this test? b. Use the five steps of hypothesis testing to answer the question. c. Write up your conclusion as if it were for a publication

Answer 1