Negative Binomial Distribution Variance Calculator

Negative Binomial Distribution Variance Calculator

For a negative binomial distribution (the number of failures \(X\) before the \(r\)th success) with failure probability \(p\) (and success probability \(1-p\)), the variance is given by: $$ \sigma^2 = \frac{r\,p}{(1-p)^2}. $$

* Enter the number of successes \(r\) (integer \(\ge 1\)) and the failure probability \(p\) (with \(0 < p < 1\)).

Step 1: Enter Parameters

e.g., 3

e.g., 0.4 ( \(0 < p < 1\) )

Formula: $$ \sigma^2 = \frac{r\,p}{(1-p)^2}. $$

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