# NEGBINOMDIST Function in Excel – Calculate Negative Binomial Distribution in Excel

NEGBINOMDIST Function in Excel calculates the Negative Binomial Distribution for a given set of parameters. Negative binomial distribution gives the probability that there will be a specified number of failures before a required number of successes is achieved.

Negative Binomial Distribution Formula:Negative Binomial Distribution Formula for rth success occurring on xth trial is shown below

Where

x: is the number of trials
r: The required number of successes.
p: The probability of success on an individual trial.
q: The probability of failure on an individual trial (q= 1-p)

#### Syntax of NEGBINOMDIST Function in Excel:

NEGBINOMDIST( number_f, number_s, probability_s )

Where,

number_f – The number of Failures encountered before the number of success.

number_s  –  The number of successes

probability_s – The probability of success(for a single trial).

#### Example of NEGBINOMDIST Function in Excel:

Let’s take an Example of Negative Binomial Distribution Function for the probability that the toss of a coin will result in exactly X Heads before 5 tossed Tails.

##### Result:

When we plot the above result with number of failures before the success on x axis. We will get the graph.