Exam 13: Quasi-Experiments and Small-N Designs

Which of the following designs has elements of both a within-group design and an independent-groups design?

RESEARCH STUDY 13.1: 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 concern/appearance concern (the Body Concern Scale). 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 3 weeks before and the 3 weeks after.This type of design is known as a(n):

RESEARCH STUDY 13.2: Dr.LaGuardia is a cognitive neuroscientist who is interested in the effect of brain concussions on the ability to recognize faces.He conducts a quasi-experimental study in which he examines football players before and after the regular season using the Benton Facial Recognition Test (a published, widely used measure of one's ability to recognize faces) to compare those who received concussions to those who did not.He finds that players who had concussions during the regular season performed worse on the Benton Facial Recognition Test than did players who did not experience concussions. Which of the following makes Dr.LaGuardia's quasi-experimental study different from a correlational study?

List three small-N designs and explain how these designs address maturation.

RESEARCH STUDY 13.4: Dr.Fletcher is interested in understanding 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 concern/appearance concern (the Body Concern Scale, where higher scores indicate higher body concerns). 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 history threat to internal validity.

Researchers may be interested in how a variable changes over the course of a major event that is scheduled outside of experimental control.This is called:

Provide a reason a researcher might want to conduct a small-N design.Provide a reason why a researcher might want to avoid conducting a small-N design.

Explain why quasi-experiments offer a trade-off between internal validity and external validity.

RESEARCH STUDY 13.1: 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 concern/appearance concern (the Body Concern Scale). Which of the following would Dr.Fletcher need to do to his current study design to make it an interrupted time-series design?

Which of the following is a within-groups quasi-experimental design?

RESEARCH STUDY 13.2: Dr.LaGuardia is a cognitive neuroscientist who is interested in the effect of brain concussions on the ability to recognize faces.He conducts a quasi-experimental study in which he examines football players before and after the regular season using the Benton Facial Recognition Test (a published, widely used measure of one's ability to recognize faces) to compare those who received concussions to those who did not.He finds that players who had concussions during the regular season performed worse on the Benton Facial Recognition Test than did players who did not experience concussions. Which of the following is true regarding external validity in Dr.LaGuardia's study?

If a researcher is concerned about external validity, which of the following would you recommend with regard to conducting small-N designs?

RESEARCH STUDY 13.4: Dr.Fletcher is interested in understanding 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 concern/appearance concern (the Body Concern Scale, where higher scores indicate higher body concerns). 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.

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

RESEARCH STUDY 13.3: Dr.Anderson is a nutritionist who helps clients lose weight prior to surgery.She is working with W.J., a male client who is 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 W.J.reduce the number of calories he eats.A food journal is used to record everything a person eats to help patients be more aware of what they're eating.W.J.'s wife also recorded the food he consumed at each meal to have complete data before introducing the journal.Dr.Anderson decides to phase in the food journal gradually, initially only having W.J.record what he ate 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.The data for Dr.Anderson's study are below. Which of the following is evidence that would allow Dr.Anderson to conclude that keeping a food journal caused weight loss in W.J.?

RESEARCH STUDY 13.4: Dr.Fletcher is interested in understanding 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 concern/appearance concern (the Body Concern Scale, where higher scores indicate higher body concerns). 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 3 weeks before and the 3 weeks after.Based on the results below, explain whether Dr.Fletcher should be concerned about a testing threat to internal validity.

RESEARCH STUDY 13.4: Dr.Fletcher is interested in understanding 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 concern/appearance concern (the Body Concern Scale, where higher scores indicate higher body concerns). 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?

RESEARCH STUDY 13.3: Dr.Anderson is a nutritionist who helps clients lose weight prior to surgery.She is working with W.J., a male client who is 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 W.J.reduce the number of calories he eats.A food journal is used to record everything a person eats to help patients be more aware of what they're eating.W.J.'s wife also recorded the food he consumed at each meal to have complete data before introducing the journal.Dr.Anderson decides to phase in the food journal gradually, initially only having W.J.record what he ate 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.The data for Dr.Anderson's study are below. In examining the external validity of her study, Dr.Anderson is probably most concerned about making sure her study generalizes to:

RESEARCH STUDY 13.3: Dr.Anderson is a nutritionist who helps clients lose weight prior to surgery.She is working with W.J., a male client who is 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 W.J.reduce the number of calories he eats.A food journal is used to record everything a person eats to help patients be more aware of what they're eating.W.J.'s wife also recorded the food he consumed at each meal to have complete data before introducing the journal.Dr.Anderson decides to phase in the food journal gradually, initially only having W.J.record what he ate 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.The data for Dr.Anderson's study are below. Which of the following aspects of Dr.Anderson's study might be susceptible to observer bias?

Which of the following is an advantage of using quasi-experimental designs?