Dr. Mankasingh is studying the potential causal relationship between engaging in retrieval practice and grades. In January, Dr. Mankasingh has her students report their fall GPA (a measure of grades achieved) and estimate how many hours they spent engaging in retrieval practice (e.g., using flashcards, completing practice tests, completing brain dumps) during a typical week in the fall semester. In May, Dr. Mankasingh measures the same variables again (the estimated number of hours spent engaging in retrieval practice during a typical week in the winter semester and their winter GPA). She finds the following correlations.

a. What type of study design is Dr. Mankasingh using? For Dr. Mankasingh to make the claim that retrieval practice causes improved grades, which correlation does she predict will NOT be significant? Note: You can answer by referring to the correlation #s in the table (e.g., Correlation 1).

b. Based on her pattern of correlations, what can Dr. Mankasingh safely conclude about the relationship between retrieval practice and grades? Explain how Dr. Mankasingh's data support your conclusion.

c. Imagine that Dr. Mankasingh hypothesized a cyclical, reinforcing relationship between retrieval practice and grades. For this to be case, which correlations would need to be significant? Note: You can answer by referring to the correlation #s in the table (e.g., Correlation 1).

d. A colleague of Dr. Mankasingh's questions her claim about the relationship between retrieval practice and grades. They are wondering whether the relationship between retrieval practice and grades could be explained by a student's working memory capacity. Specifically, they think that students who have larger working memory capacity might be more inclined to engage in retrieval practice activities and would have higher GPAs. If the colleague is correct, would working memory capacity be a moderator, a mediator, or a third variable? Propose a solution Dr. Mankasingh could use to address this colleagues' concern.

Fall number of hours of Fall semester GPA .58* retrieval practice Fall number of hours of Winter semester GPA .27* retrieval practice Fall number of hours of Winter number of hours .36* retrieval practice of retrieval practice Correlation 1 Correlation 2 Correlation 3 Correlation 4 Correlation 5 Correlation 6 inter number of hours of Winter semester GPA .65* retrieval practice Fall semester GPA Winter semester GPA Fall semester GPA Winter number of hours .19 of retrieval practice *Indicates a statistically significant relationship