Variables Definitions

1. Mean Group 1: The average value of the variable being measured in Group 1.
2. SD Group 1: The standard deviation, a measure of the variability, in Group 1.
3. Mean Group 2: The average value of the variable being measured in Group 2.
4. SD Group 2: The standard deviation in Group 2.
5. Cohen's (d): The calculated effect size that represents the standardized mean difference between Group 1 and Group 2.
6. Effect Size (r): The calculated effect size correlation represents the strength and direction of the relationship between Group 1 and Group 2.

Conversion Formulas

1. Calculation of Cohen's (d):
   • pooled SD is computed as the square root of the average of the squared standard deviations of Group 1 and Group 2:

     

   • Cohen's d is then calculated using the formula:

     

2. Calculation of Effect Size (r):
   • Effect size correlation (r) is calculated using the formula:

     

Note: (d) and (r) are positive if the mean difference is in the predicted direction.

Formula Reference