Final answer:
The blank in the student's equation would be filled with the result of (.6631)², representing the coefficient of determination, r², which is approximately 0.44 or 44%.
Step-by-step explanation:
The question pertains to the calculation of the coefficient of determination, commonly denoted as r², in a statistical context.
The coefficient of determination r² is the square of the correlation coefficient r, and it represents the proportion of the variance in the dependent variable that is predictable from the independent variable.
In the case provided, the correlation coefficient is r = .6631, therefore r² is equal to (.6631)². The value of r² in this student's question would be filled in with the result of (.6631)², which is approximately 0.44 or 44%.
This indicates that roughly 44 percent of the variation in final exam grades can be explained by the grades on the third exam.