5. Effect size for independent-measures t test - Cohen'sd and r squared Tobacco companies have actively attempted to remake their public image by launching a youth smoking prevention advertisement campaign. Melanie Wakefield (a professor of applied psychology and researcher at the Center for Behavioral Research in Cancer in Victoria, Australia) and her colleagues conducted a study to assess the relation between exposure to tobacco companies' youth smoking prevention advertising and youth smoking-related beliefs, intentions, and behaviors. You use Professor Wakefield's research to design an experiment with two groups of middle school students from Morocco. You show the tobacco company's youth smoking prevention ads to one of the groups of students every day for a week at the beginning of their math class. After the week, you assess the groups on the degree to which the students approve/disapprove of adults smoking, using a 5-point Likert scale. You do not have a prediction about the effect of the ads, as they are supposed to prevent smoking, but Professor Wakefield's findings suggested the ads might have the opposite effect if they have any effect at all. There are 81 students in each group. The first group, who saw the ads, scored an average of 3.4 with a sample standard deviation of 1.2 on the 5- point Likert scale. The second group, who did not see the ads, scored an average of 2.6 with a sample standard deviation of 1.4 on the 5-point Likert scale. You find that the estimated standard error of the difference in means is 0.2049, the estimated Cohen's d is the t statistic is 3.90, and the r2 is

MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
icon
Related questions
Question
5. Effect size for independent-measures t test - Cohen's d and r squared
Tobacco companies have actively attempted to remake their public image by launching a youth smoking prevention advertisement campaign. Melanie
Wakefield (a professor of applied psychology and researcher at the Center for Behavioral Research in Cancer in Victoria, Australia) and her colleagues
conducted a study to assess the relation between exposure to tobacco companies' youth smoking prevention advertising and youth smoking-related
beliefs, intentions, and behaviors.
You use Professor Wakefield's research to design an experiment with two groups of middle school students from Morocco. You show the tobacco
company's youth smoking prevention ads to one of the groups of students every day for a week at the beginning of their math class. After the week,
you assess the groups on the degree to which the students approve/disapprove of adults smoking, using a 5-point Likert scale. You do not have a
prediction about the effect of the ads, as they are supposed to prevent smoking, but Professor Wakefield's findings suggested the ads might have the
opposite effect if they have any effect at all.
There are 81 students in each group. The first group, who saw the ads, scored an average of 3.4 with a sample standard deviation of 1.2 on the 5-
point Likert scale. The second group, who did not see the ads, scored an average of 2.6 with a sample standard deviation of 1.4 on the 5-point Likert
scale.
You find that the estimated standard error of the difference in means is 0.2049, the estimated Cohen's d is
the t statistic is 3.90, and the
r2 is
Using Cohen's d and Cohen's criteria for evaluating Cohen's d, this is a
effect size. Using r2 and Cohen's criteria for evaluating
r2, this is a
effect size.
Hint: There is some subjectivity when applying verbal labels to numerical values. If the Cohen's d or r2 value falls between two categories,
acknowledge both categories-for example, small to medium if it is between small and medium.
Transcribed Image Text:5. Effect size for independent-measures t test - Cohen's d and r squared Tobacco companies have actively attempted to remake their public image by launching a youth smoking prevention advertisement campaign. Melanie Wakefield (a professor of applied psychology and researcher at the Center for Behavioral Research in Cancer in Victoria, Australia) and her colleagues conducted a study to assess the relation between exposure to tobacco companies' youth smoking prevention advertising and youth smoking-related beliefs, intentions, and behaviors. You use Professor Wakefield's research to design an experiment with two groups of middle school students from Morocco. You show the tobacco company's youth smoking prevention ads to one of the groups of students every day for a week at the beginning of their math class. After the week, you assess the groups on the degree to which the students approve/disapprove of adults smoking, using a 5-point Likert scale. You do not have a prediction about the effect of the ads, as they are supposed to prevent smoking, but Professor Wakefield's findings suggested the ads might have the opposite effect if they have any effect at all. There are 81 students in each group. The first group, who saw the ads, scored an average of 3.4 with a sample standard deviation of 1.2 on the 5- point Likert scale. The second group, who did not see the ads, scored an average of 2.6 with a sample standard deviation of 1.4 on the 5-point Likert scale. You find that the estimated standard error of the difference in means is 0.2049, the estimated Cohen's d is the t statistic is 3.90, and the r2 is Using Cohen's d and Cohen's criteria for evaluating Cohen's d, this is a effect size. Using r2 and Cohen's criteria for evaluating r2, this is a effect size. Hint: There is some subjectivity when applying verbal labels to numerical values. If the Cohen's d or r2 value falls between two categories, acknowledge both categories-for example, small to medium if it is between small and medium.
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 3 steps

Blurred answer
Similar questions
Recommended textbooks for you
MATLAB: An Introduction with Applications
MATLAB: An Introduction with Applications
Statistics
ISBN:
9781119256830
Author:
Amos Gilat
Publisher:
John Wiley & Sons Inc
Probability and Statistics for Engineering and th…
Probability and Statistics for Engineering and th…
Statistics
ISBN:
9781305251809
Author:
Jay L. Devore
Publisher:
Cengage Learning
Statistics for The Behavioral Sciences (MindTap C…
Statistics for The Behavioral Sciences (MindTap C…
Statistics
ISBN:
9781305504912
Author:
Frederick J Gravetter, Larry B. Wallnau
Publisher:
Cengage Learning
Elementary Statistics: Picturing the World (7th E…
Elementary Statistics: Picturing the World (7th E…
Statistics
ISBN:
9780134683416
Author:
Ron Larson, Betsy Farber
Publisher:
PEARSON
The Basic Practice of Statistics
The Basic Practice of Statistics
Statistics
ISBN:
9781319042578
Author:
David S. Moore, William I. Notz, Michael A. Fligner
Publisher:
W. H. Freeman
Introduction to the Practice of Statistics
Introduction to the Practice of Statistics
Statistics
ISBN:
9781319013387
Author:
David S. Moore, George P. McCabe, Bruce A. Craig
Publisher:
W. H. Freeman