NEGBINOMDIST

Syntax:

NEGBINOMDIST ( number-failures , number-successes , success-probability )

Description: Computes the negative binomial distribution. NEGBINOMDIST returns the probability that there will be number-failures failures before the number-successesth success, when the constant probability of a success is success-probability.

Mathematical Formula:

where:

x is number-failures, r is number-successes, and p is success-probability.

Arguments:

Name	Type	Description
number-failures	number	The number of failures, truncated to integer.
number-successes	number	The threshold number of successes, truncated to integer.
success-probability	number	The probability of a success.

 

Return Type and Value: number – The negative binomial distribution.

However, if

• number-failures < 0 or number-successes < 1, #NUM! is returned.

• success-probability < 0 or success-probability > 1, #NUM! is returned.

[Example:

NEGBINOMDIST(6,10,0.5) results in 0.076370239

end example]