Question

An independent-measures research study with n = 5 participants in each treatment produces sample variances of 8 and 10, and a 2-point difference between the two treatment means. given this information, what is the value of cohen's d? 2/2 2/3 2/9 2/18

Answer 1

Cohen's d is given by:

$Cohen's\ d= \frac{mean\ difference}{ \sqrt{ \frac{(n_1-1)s_1^2+(n_2-1)s_2^2}{n_1+n_2-2} } } \\ \\ = \frac{2}{\sqrt{\frac{(5-1)8+(5-1)10}{5+5-2}}} = \frac{2}{ \sqrt{ \frac{32+40}{8} } } = \frac{2}{ \sqrt{9} } \\ \\ =\frac{2}{3}$