How this calculation works
Swapping the samples changes the sign of d and leaves its magnitude unchanged.
THE FORMULA
d = (mean₁ − mean₂)/pooled sample standard deviationA worked example
Means 12 and 10 with pooled standard deviation 2 give d = 1.
Good to know
This is uncorrected Cohen’s d. It requires positive pooled spread.
Reference: OpenStax Introductory Statistics (opens in a new tab) ↗
Read the result
Express a difference between independent sample means in pooled standard deviation units.
The primary result is labeled “Cohen’s d”. Keep the input definitions in view when comparing this result with another method.
Try a related calculation
This is uncorrected Cohen’s d. It requires positive pooled spread.
For a related exercise, try the statistics calculator.
A few questions, answered
How can I check the default inputs by hand?
Means 12 and 10 with pooled standard deviation 2 give d = 1.
Which rule does this calculator apply?
d = (mean₁ − mean₂)/pooled sample standard deviation