Refer to Exercise 14 for a description of a study about offering college students monetary rewards.
Exercise 14
Would monetary rewards motivate you to pass more classes? In a two-semester study, researchers randomly assigned 1019 low-income community college students who were parents into two groups. Each member of the first group received a $20 gift card. Each member of the second group received the gift card plus monetary rewards for enrolling in classes, staying enrolled in classes, and maintaining at least a C average. Students in the second group could be awarded as much as $2000. The researchers concluded that monetary rewards increase the number of credits earned by low-income community college students who are parents.
a. Explain why it would be impossible to use a placebo in this study.
b. Explain why it would be impossible to redesign this study to be double-blind.
c. What are the explanatory and response variables?
d. What is the conclusion of the study? Does this mean there is causality or only an association between the two variables? Explain.
e. Three students in the control group were mistakenly given monetary rewards. Why is it important this was stated in the article?