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 \(0 < p < 1\)).