A researcher wants to see whether people are more likely to donate money to a charity when they receive a small gift from that charity. She sends an appeal for money from the charity to 1000 people

For half of the people (randomly chosen) the letter includes free address labels and for half it does not. The researcher then sees whether those who got the address labels donate more money. Which of the following is true about this study?

a. It uses the correlational method.
b. The independent variable is whether people got address labels and the dependent variable is how much money they donate.
c. The independent variable is how much money people donate and the dependent variable is whether they got address labels.
d. The study is low in internal validity because the people who got the address labels may differ in other ways from the people who did not.

Answer: B