If an experimental group's mean of 20 indicates fewer undesirable symptoms than the control group's mean of 25,and the standard deviation is 10,then the Cohen's d effect size should be reported as:

Question

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Cohen's d = (M1 - M2) / SD, where M1 is the mean of the experimental group, M2 is the mean of the control group, and SD is the standard deviation. In this case, Cohen's d = (20 - 25) / 10 = -0.5. However, Cohen's d is typically reported as a positive value, so the correct answer is A: +0.50.

If an Experimental Group's Mean of 20 Indicates Fewer Undesirable