Question

For an independent-measures research study, the two sample means are found to be M1 = 15.5 and M2 = 17. If the pooled variance is 1.23, what would be the reported value of Cohen's d, and how would the effect size be described? a. 1.22, which demonstrates a small effect size b. 1.35, which demonstrates a large effect size c. –1.22, which demonstrates a medium effect size d. –1.35, which demonstrates a large effect size

Answer 1

Option b) 1.35, which demonstrates a large effect size

Explanation:

According to the question , for an independent-measures research study, the two sample means are found to be M1 = 15.5 and M2 = 17. If the pooled variance is 1.23.

Therefore the data are given as:

,   and  

As we know that the, Cohen's d measured the effect size with the help of two mean and standard deviation as follows:

Effect size calculation Criteria as follows:

• = negative difference/ large effect
• = no difference/effect
• positive difference/large effect

Therefore,

Therefore which demonstrates a large effect size.