The following are short descriptions of research projects. For each scenario, identify the following: (a) Independent variable(s) and the dependent variable. (b) Hypothesis that the researcher appears to be testing (you will have to infer this from your reading of the scenario). (c) Empirical method that the researcher used. (d)Aspects of the research design influencing our evaluation of internal validity. (e) Aspects of the research design influencing our evaluation of external validity. (f) Changes you would make to the study to improve the internal and external validity.

(i) A researcher wants to determine whether there is a sex difference in helping behavior. To study this difference, the researcher has a male friend pose as a motorist who needs help in changing a tire. The researcher counts the number of men and women who offer to help. The data suggest that men are 50 times more likely to offer help to the motorist. The researcher concludes that men are more helpful than women.

(ii) An accounting professor was interested in examining the effects of a freshman course, Career Preparation for Accountants. The researcher assumed that students appreciation for the course would increase as they progressed through school. The professor distributed a survey to the seniors and found that the majority of the students endorsed the statement, I enjoyed my Career Preparation for Accountants course. The professor reported to the dean that the course had succeeded at preparing students for success in the business school.

(iii) A psychologist convinced a large corporation that she had a yearlong training program that increases the effectiveness of a salesperson. Impressed by the claim, the personnel director required 15 newly hired salespeople to participate in the training program. All 15 had worked for approximately 18 months as salespeople. During the year, the salespeople continued their sales work as well as spending 3 h a week in the sales seminar. At the end of the year, sales for all 15 salespeople had increased by a significant amount. The personnel director decided that all new salespersons would take the seminar as a part of their training.