# Effect Size (Cohen’s D) for T-Test

 Mean 1: Mean 2: Pooled Standard Deviation:

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Formula:`d = (mean1 - mean2) / s`

## 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.

Tags: Statistics, Effect Size, Test