A researcher observes that the mean difference between two conditions is 2.0 and the average variability in participants' scores is 4.0.The effect size,Cohen's d,for this experiment is _______.

Question

Quizplus · Accepted Answer

Cohen's d is calculated by dividing the mean difference between two conditions by the standard deviation of the participants' scores. Since the average variability is 4.0, we can estimate the standard deviation to be approximately 4.0. Therefore, Cohen's d is 2.0/4.0 = 0.5. Choice D is the correct answer. Choices A, B, and C are incorrect.

A Researcher Observes That the Mean Difference Between Two Conditions