Ch.8

40. Professor Rose was asked to design an experiment to test whether obese people would lose weight on a Pickup diet plan. Professor Rose was not a methodologist. Rose asked for your help. You immediately told Rose that the selected design would have to be sensitive to the issues of statistical regression, mortality, and demoralization. Rose said, "I don't understand." Explain these issues to Rose. Suggest and explain a design that would control for these problems. Short Essay:

Typical answers will define statistical regression as a concern with the fact that the study is using people who have extreme weights and consequently, they can only lose weight. Mortality refers to dropping out of the study. People may drop out because they do not like the diet or because the study is conducted over a prolonged period of time and they lose interest. Demoralization refers to feelings of deprivation within the control group and so they give up; they have not lost any weight. The classical experimental design would control for these issues.

24. The problem of external invalidity refers to the generalizability of results.

a. True

29. It has been suggested that within a large enough experiment and with truly randomized assignment to experimental and control groups, a pretest is unnecessary.

a. True

30. With a large pool of subjects, randomization is the preferred technique for assigning subjects to experimental and control groups even when you CAN specify in advance the relevant matching variables.

a. True

37. A fully representative sample is not as essential in experimental research, because we are measuring effects on the individual, not the individual themselves.

a. True

38. An interaction between the testing situation and the experimental stimulus jeopardizes generalizability.

a. True

17. Pre-experimental designs:

a. are the weakest experimental designs.

2. The Solomon four-group design utilizes how many control groups?

b. 2

16. In Professor John's three week experiment, the control group has realized that the experimental group is being exposed to lavish lunches as part of the experiment, while they are stuck with plain microwaved meals. In protest, they have decided to stop full participation. Which form of internal invalidity does Professor John have to worry about?

b. Demoralization

28. The use of an experimental group allows the researcher to control for the effects of the experiment itself.

b. False

19. The difference between the experimental and control group should be:

b. that the experimental group receives the independent variable and the control group does not.

21. You were asked to participate in an experiment to test the effectiveness of review sessions on exam grades. As a research methods student, you concluded that you had been assigned to the control group because you simply took the scheduled exams. Since you were in the control group you simply gave up and quit studying. This exemplifies:

c. demoralization.

14. A researcher administered a math test to a group of 9th graders in September. During the school year these students received an intensive program designed to improve their math skills. In May the math test was again given to these students and their math scores improved. A major problem in this research is that the researcher failed to control for:

e. all of these choices.

41. Explain how a natural experiment differs from a traditional one. What are the advantages and shortcomings of using them? Short Essay:

Answers should focus on the fact that the stimulus and group assignment is largely out of the control of the researcher, since he or she is using an existing situation. The advantage is it allows researchers to study situations where they cannot, either ethically or practically, construct the same situation as an experiment. The shortcomings are that the researcher has significantly less control when compared to other experimental contexts.

42. Explain what is meant by internal and external invalidity. Short Essay:

Answers should include the idea that internal invalidity refers to whether the experimental stimulus is producing the change on the dependent variable or whether there is an alternate explanation. Students might describe some of the alternate explanations (e.g., history, maturation, statistical regression). External invalidity refers to the generalizability of the results.

25. Experimental mortality encompasses more than just the death of participants.

a. True

26. In a natural experiment, the researcher does NOT manipulate the independent variable.

a. True

27. Instrumentation is NOT a threat to internal invalidity in the one-shot case study.

a. True

32. The effectiveness of randomization in experimentation is affected by the number of subjects involved.

a. True

33. For the most part, pre-experimental designs are simplified forms of the traditional experiment.

a. True

35. The double blind experiment attempts to guard against experimenter bias.

a. True

18. The Solomon four-group design:

a. combines the classical experimental design with the posttest-only control group design.

1. Among the requirements for the classical experimental design is a posttest measurement of the:

a. dependent variable for both the experimental and control groups.

13. Which of the following would constitute a "natural" experiment?

b. Doing a comparative analysis of families that choose to stay and those who choose to move out of a racially changing neighborhood to find out the underlying causes for the difference in their choices

31. The dependent variable is also known as the experimental stimulus.

b. False

34. Researchers tend to use probability sampling to recruit subjects for the experimental and control groups.

b. False

36. Because experiments focus on determining causation, they are better suited to descriptive purposes rather than explanatory purposes.

b. False

39. Typically, research on the World Wide Web involves representative samples.

b. False

9. The classical experimental design:

b. helps guard against the sources of internal invalidity.

7. An instrumentation effect occurs when:

b. the measurement instrument is changed from the pretest to the posttest.

8. The experimental and control groups should be comparable on:

b. variables that are likely to be related to the dependent variable under study.

12. The question of internal invalidity refers to:

b. whether the experimental stimulus really affected the dependent variable.

23. Jimmy's experiment requires him to tell subjects that they will be working in pairs to solve a problem when in reality he does not care about problem-solving. Jimmy is really observing the nonverbal communication between two people who do not know each other. Which of the following statements is FALSE concerning Jimmy's research?

c. Jimmy must tell the subjects that he plans to observe their nonverbal communications.

4. The double-blind experiment is one in which:

c. neither the subjects in the experimental or control groups nor the experimenters know which are the experimental and control groups.

11. Without randomly assigning subjects, a researcher administers the experimental stimulus to the experimental group and then measures the dependent variable in both the experimental and control groups. This design is known as the:

c. static-group comparison.

5. A friend of yours, a senior, took the Graduate Record Exam in September and scored in the 99th percentile. In February, your friend took the same exam over again. This time your friend scored in the 90th percentile. As a research methods student, you told your friend that his/her lowered score was most likely due to:

c. statistical regression.

6. Which of the following experimental designs have the least explanatory power compared to the others?

d. One-shot case study

10. Experiments are especially appropriate for research projects involving all of the following EXCEPT:

d. descriptive research.

20. An experiment examines the effect of the:

d. independent variable on the dependent variable.

15. Assume that you have developed a study technique that you believe will result in students scoring higher on research methods exams. You test your study technique with the design diagramed below. R=random assignment O=observation X=stimulus R O1 X O2 RO3 O4

e. O2 should be greater than O1 and the (O2-O1) change should be greater than the (O4-O3) change

3. In order to ensure that experimental and control groups are similar before the experiment begins, social scientists sometimes:

e. engage in activities mentioned in all of these choices.

22. Kyo is looking to perform a quick research study to determine the effects of a documentary about domestic violence on people's perceptions of violence. His experiment consists of administering a brief survey to a group, having them watch a movie, then surveying them as they leave to determine if any change occurred. What kind of design is Kyo utilizing?

e. one group pretest-posttest