Exam 13: Quasi-Experiments and Small-N Designs

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

The degree to which a quasiexperiment supports a causal claim depends on which of the following:

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

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

Which of the following is NOT a small-N design?

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:

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.

Which of the following is NOT an advantage of using quasi-experimental designs?

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.Dr.Anderson decides to phase in the food journal gradually,initially only recording what is eaten 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 entries from 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. -Which of the following aspects of Dr.Anderson's study might be susceptible to observer bias?

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

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?

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 three days,treats her for three days and monitors her,and then just monitors her for three more days. -Imagine that Ryan and Layne's study finds the following pattern of results.Explain why the data below are especially convincing because of the second baseline/reversal.Name a specific threat that these data address.

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

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?

Which of the following is true of the difference between large-N experiments and small-N experiments?

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.Dr.Anderson decides to phase in the food journal gradually,initially only recording what is eaten 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 entries from 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. -Which of the following does NOT allow Dr.Anderson to conclude that keeping a food journal caused weight loss in W.J.?

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

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 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.

Which of the following topics would NOT be especially well-suited to a quasi-experimental design?

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 three days,treats her for three days and monitors her,and then just monitors her for three more days. -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 the graph,B indicates baseline and T indicates Treatment. )