Exam 13: Quasi-Experiments and Small-N Designs

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.

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. -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.

Which of the following people would be of most interest for a small-N design?

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 interrogating the construct validity of Dr.LaGuardia's study,which of the following statements is accurate?

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

In conducting quasi-experimental designs,researchers tend to give up some ________ in exchange for ________.

In small-N designs,each participant is treated:

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.This type of design is known as a/an:

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. -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?

Which of the following can NOT typically be applied to a small-N experiment?

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

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

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.

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