<< Click to Display Table of Contents >> NEGBINOMDIST (negative binomial distribution)

Note: NEGBINOMDIST is supplemented by the new function NEGBINOM.DIST with additional functionality, which is available in newer versions of Microsoft Excel (2010 or later).

Syntax:

NEGBINOMDIST(k, r, p)

Description:

This returns the negative binomial distribution (also known as Pascal distribution).

The negative binomial distribution can be used to calculate the probability of obtaining k failures before the r-th success in a random experiment with independent trials and only two possible outcomes (success or failure) with a fixed probability of p for each trial.

k is the number of failures. It must be ≥ 0.

r is the number of successes. It must be ≥ 0.

k and r should be integers. If this is not the case, PlanMaker automatically truncates the decimal places.

p is the probability of success for each trial run. It must be within the range 0 to 1.

Example:

An urn contains 1 red ball and 5 black balls. What is the probability (with the balls being returned) of drawing exactly 10 black balls (failures) before the 2nd red ball (success) is drawn?

NEGBINOMDIST(10, 2, 1/6) returns 0.04935.

See also:

NEGBINOM.DIST, BINOM.DIST.RANGE/BINOM.DIST/BINOMDIST, HYPGEOM.DIST/HYPGEOMDIST