Concept explainers
The paper “Feedback Enhances the Positive Effects and Reduces the Negative Effects of Multiple-Choice Testing” (Memory & Cognition [2008]: 604–616) describes an experiment to investigate the effects of two factors on performance on a multiple-choice exam. The response variable was the percentage correct on a multiple-choice exam and the two factors of interest were
Subjects were randomly assigned to one of the nine treatments corresponding to the nine prior study and number of choices combinations. Mean percentage correct for each of the treatments are shown in the accompanying table.
- a. The authors concluded that there was no interaction between prior study and number of choices. Construct a graph of the treatment means (similar to those of Figure 15.8). Does this graph support the conclusion of no interaction? Explain.
- b. The paper also included the following F statistic values for testing main effects of prior study and number of choices.
The error df was reported as 69. Carry out appropriate tests to determine if the authors’ conclusion of significant main effects for both prior study and number of choices is justified.
- c. Based on your answers from Parts (a) and (b), write a few sentences describing the effect of prior study and the effect of number of choices on percentage correct.
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Chapter 15 Solutions
Introduction to Statistics and Data Analysis
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