This negative binomial calculator can help you calculate the negative probability based on the number of trials (n), number of successes (x) and probability of success on a single trial (p).

Number of trials [n]:*
Number of successes [x]:*
Probability of success on a single trial [p]:*

## What is a negative binomial experiment?

In statistics, a negative binomial experiment is an experiment having the following particularities:

■ The experiment is made of x repeated trials, while each trial can be considered either a success or a failure.

■ On every trial, the probability of success is constant, while the trials are independent as the outcome on a trial does not have any impact on the other trials success or failure.

■ Finally, a negative binomial experiment ends only when a specific number of successes established in advance is achieved.

## How does this negative binomial calculator work?

The algorithm behind this negative binomial calculator uses the following formula:

NB(n; x, P) = n-1Cx-1 * Px * (1 - P)n – x

Where:

p = Probability of success on a single trial

n = Number of trials

x = Number of successes

28 Jul, 2015