Question

Imagine that a researcher is conducting a paired-samples t test. She finds that the sample mean difference is 3.665, the standard deviation of the difference scores is 9.334, and the sample size is 75. The researcher is also using a typical null hypothesis that proposes no differences between the relevant population means. Under these circumstances, what is the value of Cohen's d? Please retain a minimum of three decimal places for all steps (if relevant) and provide a minimum of three decimal places when writing your answer.

Answer 1

Solution:

Cohen’s d = Mean difference / Standard deviation of the differences

d = MD / SD

d = 3.665 / 9.334

d = 0.392651

d = 0.393

So, this indicates medium effect.