# Effect Size Calculator – Cohen’s d

Instructions: This Statistics calculator will compute the Cohen’s d for you. Please provide the information required below:

Sample Mean ($$\bar X$$)
Population Mean ($$\mu$$)
Population St. Dev. ($$\sigma$$)

Cohen’s d corresponds to a widely used measure of effect size, that is used as an alternative (or complement) to the processes of hypothesis testing and calculation of p-values. Hypothesis testing has been subject to criticism because the p-values that are used to estimate the significance of an effect is heavily depending upon the sample size $$n$$. A effect size measure attempts to assess the size of the effect in a way that is not influenced heavily by the sample size. Cohen’s d is computed by using the following formula:
$d = \frac{|\bar X – \mu|}{\sigma}$