Question: Exam performance study. Check the assumptions for the factorial design ANOVA in Exercise.
Exercise: Exam performance study. Teaching of Psychology (August 1998) published a study on whether a practice test helps students prepare for a final exam. Students in an introductory psychology class were grouped according to their class standing and whether they attended a review session or took a practice test prior to the final exam. The experimental design was a 3 × 2 factorial design, with Class Standing at three levels (low, medium, or high) and Exam Preparation at two levels (practice exam or review session). There were 22 students in each of the 3 × 2 = 6 treatment groups. After completing the final exam, each student rated her or his exam preparation on an 11-point scale ranging from 0 (not helpful at all) to 10 (extremely helpful). The data for this experiment (simulated from summary statistics provided in the article) are saved in the PRACEXAM file. The first five and last five observations in the data set are listed below. Conduct a complete analysis of variance of the helpfulness ratings data, including (if warranted) multiple comparisons of means. Do your findings support the research conclusion that ‘‘students at all levels of academic ability benefit from a practice exam''?
