A study has 18 participants in the experimental group and 7 participants in the control group. What is the harmonic mean of these sample sizes?
A)18/(18 + 7)+ 7/(18 + 7)= .6
B)(2)(18)/(18 + 7)+ (2)(7)/(18 + 7)= 2.0
C)(2)(18)(7)/(18 + 7)= 10.08
D)(18 + 7)2/(18 + 7)= 25

Question

Quizplus · Accepted Answer

The formula for calculating the harmonic mean of two numbers is (2ab)/(a+b), where a and b are the two numbers. Using this formula with the sample sizes, we get (2*18*7)/(18+7) = 10.08. Therefore, choice C is the correct answer.

A Study Has 18 Participants in the Experimental Group and 7