Pooled Standard Deviation

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The Pooled Standard Deviation (Jacob Cohen) calculator computes the pooled standard deviation base on the size and standard deviations of two samples.

INSTRUCTIONS: Enter the following:

(n₁) Size of Sample 1
(n₂) Size of Sample 2
(s₁²) Variance of Sample 1
(s₂²) Variance of Sample 2

Pooled Standard Deviation (s): The calculator returns the pooled standard deviation as a real number

The Math / Sciences

The Cohen's D (formula) of pool standard deviation is:

`s = sqrt( ( (n_1 - 1)s_1^2 + (n_2 - 1)s_2^2 ) / (n_1 + n_2 -2) )`

where:

s = Cohen's D pooled standard deviation
n₁ = size of sample 1
n₂ = size of population 2
s₁² = variance of sample 1
s₂² = variance of sample 2

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