A researcher selects a sample of 24 college students and has them rate their liking for two advertisements aimed at improving the image of the college.The researcher finds that liking ratings significantly differed,t = 2.900.Use omega-squared to compute the proportion of variance for this result.
A) = 0.29
B) = 0.24
C) = 0.21
D)There is not enough information to answer this question.

Question

A researcher selects a sample of 24 college students and has them rate their liking for two advertisements aimed at improving the image of the college.The researcher finds that liking ratings significantly differed,t = 2.900.Use omega-squared to compute the proportion of variance for this result.
A) = 0.29 
B) = 0.24 
C) = 0.21 
D)There is not enough information to answer this question.

Quizplus · Accepted Answer

To compute omega-squared, we need to know the degree of freedom, which is n-1= 24-1=23. We can use the t-value to calculate Cohen's d, and then we can convert it to omega-squared. 
Cohen's d = t / sqrt(df + t^2) = 2.900 / sqrt(23 + 2.900^2) = 0.687
omega-squared = (d^2) / (1 + d^2) = (0.687^2) / (1 + 0.687^2) = 0.24
Therefore, the proportion of variance accounted for by the difference in liking ratings is about 0.24, which is the closest to option B.

A Researcher Selects a Sample of 24 College Students and Has