Hi,
comparing the average of 2 groups when we know each group's standard deviation: σ1, σ2
Cohen’s effect Size = | avg(x1)- avg(x2)| / σ pooled
How do you calculate the σ pooled for 2 sample z test?
σ pooled^2= (n1σ1^2+n2σ2^2)/(n1+n2) {similar to t-test}
or just a simple average σ pooled =(σ1+σ1)/2 ?
comparing the average of 2 groups when we know each group's standard deviation: σ1, σ2
Cohen’s effect Size = | avg(x1)- avg(x2)| / σ pooled
How do you calculate the σ pooled for 2 sample z test?
σ pooled^2= (n1σ1^2+n2σ2^2)/(n1+n2) {similar to t-test}
or just a simple average σ pooled =(σ1+σ1)/2 ?
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