**Introduction:** The T Test Effect Size Calculator helps quantify the magnitude of differences between two independent groups, providing valuable insights beyond statistical significance. Cohen’s d is a common measure used to express effect size in terms of standard deviations.

**Formula:** The calculator uses Cohen’s d formula, which is calculated as the absolute difference between the group means divided by the pooled standard deviation.

**How to Use:**

- Input the mean of Group 1.
- Input the mean of Group 2.
- Enter the standard deviation of Group 1.
- Enter the standard deviation of Group 2.
- Input the sample size of Group 1.
- Input the sample size of Group 2.
- Click the “Calculate” button to find the effect size.

**Example:** For instance, if Group 1 has a mean of 25, standard deviation of 4, and sample size of 30, and Group 2 has a mean of 22, standard deviation of 3, and sample size of 25, the calculator may determine an effect size of 0.8732.

**FAQs:**

*What does effect size (Cohen’s d) represent?*- Effect size quantifies the magnitude of the observed difference between groups, providing a standardized measure of practical significance.

*How is the pooled standard deviation calculated?*- The pooled standard deviation is computed using the standard deviations and sample sizes of both groups, reflecting a weighted average.

*What is considered a small, medium, or large effect size?*- Effect size interpretation varies, but generally, values around 0.2 indicate a small effect, 0.5 a medium effect, and 0.8 or higher a large effect.

**Conclusion:** The T Test Effect Size Calculator enhances the interpretation of T-test results by considering the effect size. Understanding the practical significance of differences between groups is crucial for informed decision-making in research and analysis.