Lesson 10.12: Observational Studies and Experiments

Check Your Understanding:

A recent report suggests that high school GPA is the best predictor of college completion. Researchers interviewed a random sample of college students and found that students with higher high school GPAs are more likely to graduate from college.

1. Was this an observational study or an experiment? Justify your answer.

2. What are the explanatory and response variables?

3. The principal at a certain high school had a crazy idea. He said “as students are graduating, we artificially increase their GPA by 0.10. This will increase their chances of completing college!” Do you agree? Explain.

4. Explain clearly why such a study cannot establish a cause-and-effect relationship. Suggest a variable that may be confounded with students’ high school GPAs.