UNIT II REVIEW

KEY TERMS AND CONCEPTS TO REMEMBER

1. hindsight bias, p. 38
2. theory, p. 42
3. hypothesis, p. 42
4. operational definition, p. 42
5. replication, p. 43
6. case study, p. 44
7. naturalistic observation, p. 45
8. survey, p. 47
9. sampling bias, p. 47
10. population, p. 47
11. random sample, p. 47
12. correlation, p. 51
13. correlation coefficient, p. 51
14. variable, p. 51
15. scatterplot, p. 51
16. illusory correlation, p. 53
17. regression toward the mean, p. 53
18. experiment, p. 54
19. experimental group, p. 54
20. control group, p. 54
21. random assignment, p. 54
22. double-blind procedure, p. 55
23. placebo [pluh-SEE-bo] effect, p. 55
24. independent variable, p. 55
25. confounding variable, p. 56
26. dependent variable, p. 56
27. validity, p. 56
28. informed consent, p. 62
29. debriefing, p. 62
30. descriptive statistics, p. 66
31. histogram, p. 66
32. mode, p. 67
33. mean, p. 67
34. median, p. 67
35. skewed distribution, p. 67
36. range, p. 68
37. standard deviation, p. 68
38. normal curve, p. 68
39. inferential statistics, p. 70
40. statistical significance, p. 71

AP^® EXAM PRACTICE QUESTIONS

Multiple-Choice Questions

1. A student is interested in knowing how widely the academic aptitude of college-bound students varies at her school. Which of the following statistical methods should she use to determine how much students’ SAT scores vary from the school’s average SAT score?
   1. Correlation coefficient
   2. Mean
   3. Median
   4. Standard deviation
   5. Range
2. Which method should a psychology researcher use if she is interested in testing whether a specific reward in a classroom situation causes students to behave better?
   1. Case study
   2. Experiment
   3. Survey
   4. Naturalistic observation
   5. Correlation
3. In a perfectly normal distribution of scores, which of the following statements is true?
   1. The mean, median, and mode are all the same number.
   2. The mode is equal to the standard deviation.
   3. The scores are positively correlated.
   4. The mean minus the mode equals the median.
   5. There is a positive skew to the distribution of data.
4. Which of the following describes the placebo effect?
   1. Students in art class are not told that their work will be evaluated for a scholarship.
   2. Participants in an experiment do not know if they are in the experimental or control group.
   3. Participants in a drug study are given an inert pill instead of the drug and behave as though they were given the drug.
   4. Only females are chosen for a study, even though the population included males.
   5. Experimenters manipulate one variable in a study, but not any others.
5. Which of the following represents naturalistic observation?
   1. Researchers go to the mall and distribute surveys about the stores in the mall.
   2. Researchers bring participants into a laboratory to see how they respond to a puzzle with no solution.
   3. A principal looks at the relationship between the number of student absences and their grades.
   4. Researchers observe students’ seating patterns in the cafeteria.
   5. Two grandparents sit in the front row to watch their grandson’s first piano recital.
6. “Monday morning quarterbacks” rarely act surprised about the outcome of weekend football games. This tendency to believe they knew how the game would turn out is best explained by which psychological principle?
   1. Overconfidence
   2. Hindsight bias
   3. Common sense
   4. Illusory correlation
   5. Random sampling
7. Researchers studying gender have found that
   1. there are more similarities than differences between the genders.
   2. there are no significant cognitive differences between the genders.
   3. there are no significant emotional differences between the genders.
   4. research tools are not capable of determining if there are or are not true differences between the genders.
   5. differences between the genders are becoming more pronounced over time.
8. A journalism student is writing an article about her school’s new cell-phone policy, and she’d like to interview a random sample of students. Which of the following is the best example of a random sample?
   1. The writer arrives at school early and interviews the first five students who come through the main entrance.
   2. The writer pulls the names of five students from a hat that contains all students’ names. She interviews the five selected students.
   3. The writer asks her teacher if she can distribute a brief survey to the students in her AP^® Psychology class.
   4. The writer passes out brief surveys to 50 students in the hall and uses the 18 surveys returned to her as the basis of her article.
   5. The writer asks the principal for the names of 10 students who have had their cell phones confiscated for a day for violating the policy. She interviews these 10 students.
9. Which of the following is a positive correlation?
   1. As study time increases, students achieve lower grades.
   2. As levels of self-esteem decline, levels of depression increase.
   3. People who exercise regularly are more likely to be overweight.
   4. Gas mileage decreases as vehicle weight increases.
   5. Repeatedly shooting free throws in basketball is associated with a smaller percentage of missed free throws.
10. Why is random assignment of participants to groups an important aspect of a properly designed experiment?
    1. If the participants are randomly assigned, the researcher can assume that the people in each group are similar.
    2. By randomly assigning participants, the researcher knows that whatever is learned from the experiment will also be true for the population from which the participants were selected.
    3. Random assignment keeps expectations from influencing the results of the experiment.
    4. If participants are not randomly assigned, it is impossible to replicate the experiment.
    5. Statistical analysis cannot be performed on an experiment if random assignment is not used.
11. Which of the following demonstrates the need for psychological science?
    1. Psychology’s methods are unlike those of any other science.
    2. Psychological experiments are less valuable without psychological science.
    3. Our commonsense thinking about human thoughts and behaviors is not always accurate.
    4. Commonsense thinking does not provide correct answers unless it is applied through the scientific method.
    5. Psychological science research is superior to that of other sciences such as biology and physics.
12. Which of the following is a potential problem with case studies?
    1. They provide too much detail, and the researcher is likely to lose track of the most important facts.
    2. They are generally too expensive to be feasible.
    3. The information learned may not apply to the wider population.
    4. They are technically difficult and most researchers don’t have the skills to do them properly.
    5. The dependent variable is difficult to operationally define in a case study.
13. Which of the following is not an ethical principle regarding experimental research on humans?
    1. Researchers must protect participants from needless harm and discomfort.
    2. Participants must take part in the study on a voluntary basis.
    3. Personal information about individual participants must be kept confidential.
    4. Research studies must be fully explained to participants when the study is completed.
    5. Participants should always be informed of the hypothesis of the study before they agree to participate.
14. There is a negative correlation between TV watching and grades. What can we conclude from this research finding?
    1. We can conclude that this is an illusory correlation.
    2. We can conclude that TV watching leads to lower grades.
    3. We can conclude that TV watching leads to higher grades.
    4. We can conclude that the grades students get impact their TV watching habits.
    5. We can conclude that a student who watches a lot of TV is likely to have lower grades.
15. Which of the following groups of scores would have the smallest standard deviation?
    1. 20, 40, 60, 80, 100
    2. 5, 15, 25, 35, 45
    3. 2, 4, 6, 8, 10
    4. 100, 200, 300, 400, 500
    5. 15, 30, 45, 60, 75

Use this scenario to answer questions 16–20:

Researchers wanted to find out if eating cookies would increase a person’s ability to remember the names of U.S. presidents. Thirty males and 30 females were used in the experiment. A third of these people (Group A) were given cookies while studying the names. Another third (Group B) were given nothing while studying the names. The final third (Group C) were given mint-flavored candy while studying the names. After gathering all their results, the researchers found that Group A did substantially better than Group B, but about the same as Group C.

16. The dependent variable in this study is
    1. the mint candy.
    2. the test scores.
    3. the cookies.
    4. eating any food.
    5. the list of presidents.
17. The independent variable in this study is
    1. the mint candy.
    2. the test scores.
    3. the cookies.
    4. the food treatment.
    5. the list of presidents.
18. Which of the following are the experimental group(s) of this study?
    1. Group A
    2. Group B
    3. Group C
    4. Groups A & C
    5. Groups B & C
19. Which of the following is/are the control group(s) of this study?
    1. Group A
    2. Group B
    3. Group C
    4. Groups A & B
    5. Groups B & C
20. Which of the following is the best conclusion for this study?
    1. Eating cookies will always improve memory recall.
    2. Eating cookies tends to improve memory recall.
    3. Eating cookies or mint candy tends to improve memory recall.
    4. Eating nothing is associated with poor concentration.
    5. Eating mint-flavored candy will always improve memory recall.

Free-Response Questions

1. Ryan Greene noticed an ad for an Internet dating service that claimed more people who used its service were in long-term relationships than were people who didn’t use the service. Ryan, a good critical thinker, knows this isn’t enough to claim that the service causes people to find long-term love, and he wants to create an experiment to investigate. Use the following terms to describe an experiment that would support or dispute the ad’s claim.
   • Hypothesis
   • Random sample
   • Random assignment
   • Operational definitions
   • Independent variable
   • Dependent variable
   • Inferential statistics

Rubric for Free-Response Question 1

1 point: The hypothesis in this context is that the Internet dating service causes (or leads to) long-term relationships. Page 42

1 point: Since the population of interest for this study should be people who are looking for long-term relationships, selecting a random sample of adults seeking relationships would help assure that the conclusions could be fairly generalized to the dating public. Page 47

1 point: In this case, participants should be randomly assigned to use of the Internet service (the experimental group) or not (the control group). Page 54

1 point: Ryan would need to operationally define what is meant by use of the Internet service, possibly including a precise number of visits to the website or time spent on the website. The phrase long-term relationship would also need an operational definition, possibly by the number of months together or a formal commitment (like engagement or marriage). Page 42

1 point: In Ryan’s study, the use of the online dating service is the independent variable. Page 55

1 point: The number of long-term relationships is the dependent variable. Page 56

1 point: Ryan will need to calculate statistical significance for the experimental findings. In order to claim support for the hypothesis, the results need to show that there is no more than a 5 percent chance the findings are due to chance. Page 70

2. Dr. Tabor wanted to investigate the relationship between sleep and levels of alertness. She gave surveys to 150 college freshmen in her introduction to psychology course, asking them to report how many hours they slept each night during a 2-week period. Each day at the end of class, Dr. Tabor also had the participants rate their level of alertness on a scale of 1 to 10, with 10 being the most alert. Dr. Tabor compared the average amount of sleep reported by each participant along with their average score on the alertness scale on a graph to examine the data. The resulting correlation coefficient for Dr. Tabor’s data was +0.89. Explain how each of the following concepts might apply to Dr. Tabor’s research.
   • Random sample
   • Scatterplot
   • Wording effects
   • Positive correlation
   • Operational definition

(5 points)

3. Dr. Pauling wanted to study whether vitamin C affects self-esteem. He recruited 200 people who came to his lab. Participants were told that they were about to take part in a harmless research study, and they needed to sign a release form in case there were harmful side effects from the vitamin C pills. The 100 participants on the right side of the room received a pill with vitamin C and the others on the left received a pill with caffeine. Dr. Pauling then gave each group a list of questions to answer in essay form about their self-esteem. When they were finished, he thanked the participants and sent them on their way. After compiling his findings, Dr. Pauling printed the names of the students and their results in the campus newspaper so they would know the results of the test. Dr. Pauling concluded that vitamin C had a positive effect on self-esteem. Identify five ethical violations in Dr. Pauling’s study.

(5 points)