Exam 13: Quasi-Experiments and Small-N Designs

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. In analyzing the data, Dr.LaGuardia finds that there was no pretest difference in Benton Facial Recognition scores.However, he does find that the football players who received concussions had worse visuo-spatial awareness before the study.Which of the following threats to internal validity should he be concerned with?

Which of the following is NOT a small-N 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 NOT a trade-off of Dr.Anderson's use of a small-N design?

Which of the following is an advantage of small-N designs over large-N designs?

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. If Dr.Anderson wanted to change the study to a stable-baseline design, which of the following would she change?

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 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.After conducting the study, Dr.Fletcher finds out that the people who joined a fraternity/sorority all saw a documentary on body image sponsored by the InterGreek Council the night before recruitment began.This threat to internal validity is known as a:

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). If Dr.Fletcher is interested in a causal relationship between joining a fraternity/sorority and attractiveness/appearance concern, why doesn't he conduct a true experiment?

Seeing stability in a stable-baseline design can help rule out which of the following threats to internal validity?

How does a researcher who conducts a small-N design address external validity concerns about his study?

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 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.Doing this would help Dr.Fletcher address all of the following threats to internal validity EXCEPT:

Which of the following topics would be especially well suited to a quasi-experimental design?

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

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

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

The degree to which a quasi-experiment supports a causal claim depends on which of the following?

According to the textbook, which of the following ethical questions might be posed specifically in reference to a reversal design?

In a nonequivalent control group interrupted time series design, the independent variable is studied as:

A small-N design that involves providing treatment and then removing treatment is known as a(n):

Why do quasi-experiments tend to have very good construct validity for the independent variable?

Which of the following is true of small-N experiments?