Effect Size (Cohen’s D) for T-Test

Introduction to Effect Size (Cohen’s D) for T-Test

Cohen’s D is a standardized measure of the difference between two means and is used to quantify the size of the effect in a T-Test. In the formula, d represents the effect size, mean1 is the mean of the first group, mean2 is the mean of the second group, and s is the pooled standard deviation of the two groups. A positive value indicates that the first mean is larger, and a negative value indicates that the second mean is larger. The magnitude represents the effect size relative to the standard deviation.

Parameter usage:

• mean1 = mean of the first group
• mean2 = mean of the second group
• pooledStandardDeviation = pooled standard deviation of the two groups

Output:

• d = effect size (Cohen’s D)

Data validation

The pooled standard deviation should be greater than zero.

Summary

This formula calculates the effect size (Cohen’s D) for a T-Test, providing a standardized measure of the difference between two means in relation to the pooled standard deviation. It is widely used in statistical analysis for evaluating the significance of findings.