Cohen's D Calculator
Compute Cohen's d effect size between two independent samples using pooled standard deviation.
Description
Compute Cohen's d effect size between two independent samples using pooled standard deviation.
Cohen's D Calculator is a focused tool for the following task. Compute Cohen's d effect size between two independent samples using pooled standard deviation. It reports Cohen's d from the values you provide rather than inventing measurements, coefficients, or professional judgment that are not part of the input.
When to use Cohen's D
Use this calculation to reproduce a defined quantitative method when the observations, units, sampling process, and assumptions match the method shown here.
- Mean 1
- Required number.
- Mean 2
- Required number.
- N 1
- Required integer.
- N 2
- Required integer.
- SD 1
- Required number.
- SD 2
- Required number.
The cited overview of Statistics supplies background for the terminology and domain context used by this tool.1
How Cohen's D works
Compute Cohen's d effect size between two independent samples using pooled standard deviation. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.
- Cohen's d
- Returned number.
Limitations and assumptions
- A numerical result does not by itself establish data quality, causation, representativeness, independence, distributional fit, or practical significance.
- N 1 must be at least 2.
- N 2 must be at least 2.
- SD 1 must be at least 0.
- SD 2 must be at least 0.
- Use finite inputs in the displayed units, preserve source measurements and assumptions, and independently verify consequential decisions.
Alternative or Complementary approaches
Inspect the underlying data, visualize its distribution, report uncertainty and sample size, and compare the result with a robust or domain-specific method where appropriate.
References
-
Statistics — Wikipedia contributors
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