Exam 12: Quasi-Experiments and Small-N Designs

RESEARCH QUESTION 12.4 Dr. Fletcher is interested in whether joining a fraternity/sorority causes people to become more concerned about their attractiveness and appearance. He recruits a group of 55 freshmen (25 males, 30 females) who are planning to go through fraternity/sorority recruitment on his campus. After they join, he gives them a measure of attractiveness/ appearance concern (the Body Concern Scale, where higher scores indicate higher body concerns). -Refer to Research Study 12.4 above to answer the following question. In addition to measuring the body concern of the participants who joined a fraternity/sorority immediately before and immediately after they join,Dr.Fletcher measures them for the three weeks before and the three weeks after.Based on the results below,explain whether Dr.Fletcher should be concerned about a testing threat to internal validity.

RESEARCH STUDY 12.1 Dr. Fletcher is interested in whether joining a fraternity/sorority causes people to become more concerned about their attractiveness and appearance. He recruits a group of 55 freshmen (25 males, 30 females) who are planning to go through fraternity/sorority recruitment on his campus. After they join, he gives them a measure of attractiveness/appearance concern (the Body Concern Scale). -Refer to Research Study 12.1 above to answer the following question. In addition to measuring the body concern of the participants who joined a fraternity/sorority both immediately before and immediately after they join,Dr.Fletcher measures them for the three weeks before and the three weeks after.This type of design would be able to better address which of the following threats to internal validity?

Explain why quasi-experiments and correlational studies can be seen as similar but why quasi-experiments are superior.

A wait-list design is helpful in dealing with which of the following threats to internal validity?

Which of the following is a difference between true experiments and quasi-experiments?

In interrogating the construct validity of Dr.Anderson's study,which of the following might be asked?

RESEARCH STUDY 12.5 Layne is trying to watch less television. Her friend Ryan is a psychologist who agrees to help her. He creates a treatment plan that involves giving Layne $5 for every day that she watches fewer than 90 minutes of television. He monitors her television watching for 3 days, treats her for 3 days and monitors her, and then just monitors her for 3 more days. -Refer to Research Study 12.5 above to answer the following question. Imagine that Ryan and Layne's study finds the following pattern of results.Explain whether Ryan and Layne should conclude that the $5 treatment is effective at decreasing television viewing and whether they should be concerned by an instrumentation threat.

In which of the following ways are correlational designs similar to quasi-experimental designs?

RESEARCH STUDY 12.3 Dr. Anderson is a nutritionist who helps clients lose weight prior to surgery. She is working with a client (W. J.) who is a male planning on undergoing a heart transplant. He currently eats more than 3,500 calories a day and has been asked by his doctor to cut the number of calories to about 1,800 (400 for breakfast, 600 for lunch, and 800 for dinner). She is curious as to whether a food journal will help reduce the number of calories. A food journal is a book in which a person writes down everything he or she eats. She decides to phase in the food journal gradually, initially only being used at breakfast during the first three days after baseline (days 4-6). During days 7-9, the journal is used at lunch, too, and during days 10-12, it also is used during dinner. Each day, Dr. Anderson's client sends her the food journal and the number of calories he ate at each meal (as calculated by his wife, whose help she enlisted). The data for Dr. Anderson's study are below. -Refer to Research Study 12.3 above to answer the following question. Which of the following aspects of Dr.Anderson's study might be susceptible to observer bias?

RESEARCH STUDY 12.3 Dr. Anderson is a nutritionist who helps clients lose weight prior to surgery. She is working with a client (W. J.) who is a male planning on undergoing a heart transplant. He currently eats more than 3,500 calories a day and has been asked by his doctor to cut the number of calories to about 1,800 (400 for breakfast, 600 for lunch, and 800 for dinner). She is curious as to whether a food journal will help reduce the number of calories. A food journal is a book in which a person writes down everything he or she eats. She decides to phase in the food journal gradually, initially only being used at breakfast during the first three days after baseline (days 4-6). During days 7-9, the journal is used at lunch, too, and during days 10-12, it also is used during dinner. Each day, Dr. Anderson's client sends her the food journal and the number of calories he ate at each meal (as calculated by his wife, whose help she enlisted). The data for Dr. Anderson's study are below. -Refer to Research Study 12.3 above to answer the following question. If Dr.Anderson wanted to keep the same general design,what other baselines could she use?

RESEARCH QUESTION 12.4 Dr. Fletcher is interested in whether joining a fraternity/sorority causes people to become more concerned about their attractiveness and appearance. He recruits a group of 55 freshmen (25 males, 30 females) who are planning to go through fraternity/sorority recruitment on his campus. After they join, he gives them a measure of attractiveness/ appearance concern (the Body Concern Scale, where higher scores indicate higher body concerns). -Refer to Research Study 12.4 above to answer the following question. In addition to measuring the group of participants who joined a fraternity/sorority,Dr.Fletcher decides to give the same measure to another group of 55 participants who decided to not join a fraternity/sorority.Based on the results below,explain whether Dr.Fletcher should be concerned about a maturation threat to internal validity.

List the three differences between small-N and large-N designs.

RESEARCH QUESTION 12.4 Dr. Fletcher is interested in whether joining a fraternity/sorority causes people to become more concerned about their attractiveness and appearance. He recruits a group of 55 freshmen (25 males, 30 females) who are planning to go through fraternity/sorority recruitment on his campus. After they join, he gives them a measure of attractiveness/ appearance concern (the Body Concern Scale, where higher scores indicate higher body concerns). -Refer to Research Study 12.4 above to answer the following question. As the study is described,explain a selection threat that may be present in Dr.Fletcher's study.What could Dr.Fletcher do to address this threat?

Which of the following is an independent-groups quasi-experimental design?

RESEARCH STUDY 12.3 Dr. Anderson is a nutritionist who helps clients lose weight prior to surgery. She is working with a client (W. J.) who is a male planning on undergoing a heart transplant. He currently eats more than 3,500 calories a day and has been asked by his doctor to cut the number of calories to about 1,800 (400 for breakfast, 600 for lunch, and 800 for dinner). She is curious as to whether a food journal will help reduce the number of calories. A food journal is a book in which a person writes down everything he or she eats. She decides to phase in the food journal gradually, initially only being used at breakfast during the first three days after baseline (days 4-6). During days 7-9, the journal is used at lunch, too, and during days 10-12, it also is used during dinner. Each day, Dr. Anderson's client sends her the food journal and the number of calories he ate at each meal (as calculated by his wife, whose help she enlisted). The data for Dr. Anderson's study are below. -Refer to Research Study 12.3 above to answer the following question. Dr.Natchez,a colleague of Dr.Anderson,questions whether W.J.simply wrote down less in his journal as the study went on because he grew tired of completing this "measure." Dr.Natchez believes he has uncovered which of the following threats to internal validity?

RESEARCH STUDY 12.3 Dr. Anderson is a nutritionist who helps clients lose weight prior to surgery. She is working with a client (W. J.) who is a male planning on undergoing a heart transplant. He currently eats more than 3,500 calories a day and has been asked by his doctor to cut the number of calories to about 1,800 (400 for breakfast, 600 for lunch, and 800 for dinner). She is curious as to whether a food journal will help reduce the number of calories. A food journal is a book in which a person writes down everything he or she eats. She decides to phase in the food journal gradually, initially only being used at breakfast during the first three days after baseline (days 4-6). During days 7-9, the journal is used at lunch, too, and during days 10-12, it also is used during dinner. Each day, Dr. Anderson's client sends her the food journal and the number of calories he ate at each meal (as calculated by his wife, whose help she enlisted). The data for Dr. Anderson's study are below. -Refer to Research Study 12.3 above to answer the following question. In interrogating the statistical validity of Dr.Anderson's study,which of the following might be asked?

Lara is conducting a study for her research methods class.She is curious if participating in a collegiate study-abroad program causes people to become more accepting of other cultures.Provide an example of an independent-groups quasi-experimental design and an example of a within-groups quasi-experimental design using Lara's research question.

RESEARCH STUDY 12.3 Dr. Anderson is a nutritionist who helps clients lose weight prior to surgery. She is working with a client (W. J.) who is a male planning on undergoing a heart transplant. He currently eats more than 3,500 calories a day and has been asked by his doctor to cut the number of calories to about 1,800 (400 for breakfast, 600 for lunch, and 800 for dinner). She is curious as to whether a food journal will help reduce the number of calories. A food journal is a book in which a person writes down everything he or she eats. She decides to phase in the food journal gradually, initially only being used at breakfast during the first three days after baseline (days 4-6). During days 7-9, the journal is used at lunch, too, and during days 10-12, it also is used during dinner. Each day, Dr. Anderson's client sends her the food journal and the number of calories he ate at each meal (as calculated by his wife, whose help she enlisted). The data for Dr. Anderson's study are below. -Refer to Research Study 12.3 above to answer the following question. What type of small-N design has Dr.Anderson used with W.J.?

Explain how interrogating the statistical validity of a small-N design is different from interrogating the statistical validity in a large-N design.

RESEARCH STUDY 12.5 Layne is trying to watch less television. Her friend Ryan is a psychologist who agrees to help her. He creates a treatment plan that involves giving Layne $5 for every day that she watches fewer than 90 minutes of television. He monitors her television watching for 3 days, treats her for 3 days and monitors her, and then just monitors her for 3 more days. -Refer to Research Study 12.5 above to answer the following question. What type of design is Ryan using to change Layne's behavior? Name a threat to internal validity that this design is well suited to address.