A researcher conducted a study to investigate the effects of smiling on helping behavior. Participants completed a survey that they thought was the purpose of the study, but in reality, the experiment...

A researcher conducted a study to investigate the effects of smiling on helping behavior. Participants completed a survey that they thought was the purpose of the study, but in reality, the experiment took place after they completed the survey. At the end of the survey session, half of the subjects were thanked with a smile and half were thanked without a smile. Whether the subject received a smile or not was randomly determined. The gender of the person giving the smile also varied by participant: Some subjects received the smile from a female researcher and some subjects received the smile from a male researcher. The subjects then passed a confederate in the hallway on their way out of the lab who had just dropped a large stack of books. The number of subjects who helped the confederate pick up his books was measured. The results showed that the subjects who were thanked by a male researcher showed similar helping behaviors across smile and no-smile conditions. However, subjects who were thanked by a female researcher showed more helping behaviors when they received a smile than when they did not.

a. What are the independent variables in this experiment? Identify how each independent variable was manipulated (i.e., between subjects or within subjects).

b. Explain why you think the researcher decided to compare gender of the confederate in this study.

c. From the description of the results, was an interaction present? Explain your answer.