A researcher obtains t(20)= 2.00 and MD = 9 for a repeated-measures study.If the researcher measures effect size using the percentage of variance accounted for,what value will be obtained for r²?
A)9/20
B)9/29
C)4/13
D)4/24

Question

Quizplus · Accepted Answer

The effect size r² for a repeated-measures study can be calculated using the formula r² = t² / (t² + df), where t is the t-value and df is the degrees of freedom. Here, t = 2.00 and df = 20, so r² = 2² / (2² + 20) = 4 / (4 + 20) = 4/24.

A Researcher Obtains T(20)= 2