Introductory Econometrics: A Modern Approach 6th Edition by Jeffrey M Wooldridge

Exercise 23

The data in ECONMATH contain grade point averages and standardized test scores, along with performance in an introductory economics course, for students at a large public university. The variable to be explained is score, the final score in the course measured as a percentage.

(i) How many students received a perfect score for the course? What was the average score? Find the means and standard deviations of actmth and acteng, and discuss how they compare.

(ii) Estimate a linear equation relating score to colgpa, actmth, and acteng, where colgpa is measured at the beginning of the term. Report the results in the usual form.

(iii) Would you say the math or English ACT score is a better predictor of performance in the economics course? Explain.

(iv) Discuss the size of the R-squared in the regression.