Negative Binomial Distribution CDF Calculator

For a negative binomial distribution (defined as the number of failures \(x\) before the \(r\)th success) with success probability \(p\), the CDF is: $$ F(X \le x)=\sum_{i=0}^{x} \binom{i+r-1}{i} (1-p)^r p^i,\quad x=0,1,2,\dots $$

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