PSY 230, Introduction to Statistics

Critique Questions

Dr. Jacobs

Select one of the articles linked to my web page (web.gccaz.edu/~ejacobs.) Go to “Study Resources” in the right-and column, then select “Journal Articles” (direct link = http://web.gccaz.edu/~ejacobs/Articles.htm ). Carefully read and take notes on the article and then thoroughly answer the following questions. Answers should be typed using APA format (1” margins, double spaced). Be sure to include your name, class, and class time. Check you syllabus for due dates.

1. What is the target population of this study? – Whom will the authors draw conclusions about? -- NOT who are the subjects?)

• The target population is the group of people that the researcher is interested in describing. It is not the sample used. The sample should be a representative group of people selected from the population at random. See whom the author is referring to at the beginning of the article. Is she saying, "We are interested in people’s reaction to small mammals" and then using a sample of teenage girls as her representative sample? Her population is obviously "people", yet she’s using a non=representative sample. If her opening paragraph stated, "we are interested in the reaction of teenage girls to small mammals" then her sample would be fine.

2. Who are the subjects?

• Where did the subjects come from? How old are they? How were they selected? What gender? What socioeconomic backgrounds? What ethnic backgrounds? From what geographical locations? If some of these characteristics are not reported, why not? How does not knowing the subjects’ background affect the relevance of the outcome of the study? Why? Why not?

3. Are the subjects representative of the target population? Why or why not?

• Do the subjects match the population the author is describing at the beginning of the article? How could the subjects be more representative of the population, i.e., how could the authors have improved their study by improving their subject selection?

4. What is the independent variable?

• The independent variable in an experiment is the variable that is manipulated by the experimenter. In true experimental research subjects are randomly assigned to levels of the independent variable. A researcher testing the affects of caffeine on heart rate may decide to investigate the affects of 100, 300, and 500 milligrams of caffeine. He first randomly assigns each subject to one of the three conditions and then measures the affect of the various dosages on subject heart rate.

• Some quasi-experimental research may not have a true independent variable. Although gender is the independent variable in a study investigating the

differences in honesty between males and females, the researcher is only statistically manipulating gender. He can't really randomly assign subjects to

"male" or "female." (As far as I know…)

5. What is the dependent variable?

• The dependent variable is the result of the manipulation of the independent variable. In the example for independent variable, the dependent variable is

heart rate. The researcher wants to observe what changes occur in heart rate as the result of manipulating the intake of caffeine.

6. What is the conclusion of this article?

• How do the authors summarize their findings? Is their summary a logical conclusion to their research? For example, if white mice are placed on the

shoulders of young teenage girls, can the authors conclude that all teenage girls have a phobia about small mammals? (Hint: No.)

7. For whom are these results important, i.e., who will use these results and in what way?

• You probably paid for this research with your taxes. Is it a good expenditure? Who will use the information? Psychologists? Nurses? Auto mechanics?

Physicians? Teachers? Counselors? Police Officers? Business Managers? Parents? Specifically, how will these people use that information?

8. What statistical analyses were used to draw the conclusion?

• While you won’t understand the statistical analyses used in these articles early in the semester, you should immediately recognize Means, Standard Deviations, and frequency distributions. Later in the semester you should be able to pick up analysis terms like z score, t test, F test, analysis of variance and correlation. If you find an analysis technique listed that does not look familiar, look it up in your textbook for a clarification. If there is no statistical analyses used, it is not a research article. Time to find another...

9. If this a good study from which to draw a conclusion? If yes, why? If not, why not?

• What are the article’s strengths? What are its weaknesses? How could the researchers have done it better? Would you tell others about this research? Was it money well spent?

10. How can you use, either personally or professionally, the information in this article?

• More specifically than the last question, as a professional, how would you use this information to make decisions about people with whom you work, counsel, teach, etc.? If this is an article that does not pertain to your research or interest, don’t use it for this assignment.