1. A woman developed a psychotic disorder after a car accident in which she received severe head injuries. Based on this evidence, I have concluded that head injuries cause psychosis[∂]. What of the following is the best comment to make about my conclusion?

A. I cannot conclude this because I have not ruled out the effects of extraneous variables.
B. I cannot conclude this because mental disorders, by definition, cannot have physical causes.
C. This is the most plausible conclusion because the head injuries occurred just before she developed a psychotic disorder.
D. This is the most plausible conclusion because psychosis is due to problems in the brain caused by external factors.

2. Which of the following is an example of a case study?

A. A study of 1000 people showed that those who smoked were more likely to develop lung cancer than those who did not smoke.
B. A study of an autistic girl showed that she developed autistic symptoms soon after receiving the MMR vaccine at 18 months.
C. A study of a new antidepressant showed that a group given the medication improved more than did a group given a placebo.

3. Which of the following is a major weakness of case studies?

A. Case studies do not allow us to determine if one event is causing another event.
B. Case studies do not allow us to determine if one event is linked to a second event.
C. Case studies do not allow us to determine if a particular behavior is harmful.
D. Case studies do not allow us to determine if a person has a mental disorder.

4. Students who sit in the first few rows of a classroom tend to perform better on tests than do students who sit in the last few rows. One possible explanation is that, compared to students in the last few rows, students who sit in the first few rows tend to be more attentive and involved because they are closer to the teacher. Which of the following alternative explanations includes an extraneous variable that is most likely to be another possible cause of the association between test performance and seat location?

A. Levels of visual skills are most likely to differ between students who sit in front and students who sit in back.
B. Levels of motor activity are most likely to differ between students who sit in front and students who sit in back.
C. Levels of motivation to do well are most likely to differ between students who sit in front and students who sit in back.

5. I wanted to determine if giving daily quizzes improved test scores in PSY 101. I gave daily quizzes in my 10:30 AM section, but did not give daily quizzes in my 7:30 AM section. At the end of the semester, I found that students in the 10:30 AM section received higher average test scores than did students in the 7:30 AM section. Which two variables are confounded in this study?

A. Giving daily quizzes is confounded with average test score.
B. Average test score is confounded with class meeting time.
C. Giving daily quizzes is confounded with class meeting time.
D. Class meeting time is confounded with average test score.

6. Several months after his father's death, a man began thinking about Mr. Rogers, the former host of a popular children's television show: "He's getting pretty old; I'll bet that he will die soon." The man was shocked when he woke up the next morning and heard on the news that Mr. Rogers had died the night before. The man concluded that he must have had a psychic premonition concerning Mr. Rogers' death. What is the best comment to make about this conclusion?

A. We cannot conclude this because scientists have proven that psychic experiences are not possible.
B. We cannot conclude this because the effects of extraneous variables have not been controlled.
C. This is the most plausible conclusion because the man thought about Mr. Rogers first and only later heard that he had died.
D. This is the most plausible conclusion because the man felt strongly that he had had a psychic experience.

7. When testing a particular theory, which of the following should be the most important component of one's research?

A. ruling out assumptions and concepts
B. ruling out alternative explanations
C. comparing a number of case studies
D. comparing a number of correlational studies

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