NEGBINOM.DIST

NEGBINOM.DIST(number_f, number_s, probability_s, cumulative)

Returns the probability of getting less than or equal to a particular value in a negative binomial distribution.

number_f	The number of failures.
number_s	The threshold number of successes.
probability_s	The probability of a success.
cumulative	A logical value indicating the type of function to use: True = cumulative probability function False = probability mass function

REMARKS

* This function replaces the NEGBINOMDIST function.
* The negative binomial distribution is a discrete distribution.
* This function returns the probability that there will be "number_f" failures before the "number_s"-th success, when the constant probability of a success is "probability_s".
* For example, you need to find 10 people with excellent reflexes, and you know the probability that a candidate has these qualifications is 0.3.
* This function calculates the probability that you will interview a certain number of unqualified candidates before finding all 10 qualified candidates.
* The "number_f" and "number_s" are truncated to integers.
* If any of the arguments are not numeric, then #VALUE! is returned
* If "probability_s" < 0, then #NUM! is returned.
* If "probability_s" > 1, then #NUM! is returned.
* If ("number_f" + "number_s" - 1) = 0, then #NUM! is returned.
* The equation for the negative binomial distribution is: ??
* Added in Excel 2010.
* For the Microsoft documentation refer to support.microsoft.com

	A
1	=NEGBINOM.DIST(0,1,0.25,FALSE) = 0.25
2	=NEGBINOM.DIST(0,1,0.5,FALSE) = 0.5
3	=NEGBINOM.DIST(1,6,0.5,FALSE) = 0.047
4	=NEGBINOM.DIST(10,5,0.25,FALSE) = 0.055
5	=NEGBINOM.DIST(10,5,-4,FALSE) = #NUM!
6	=NEGBINOM.DIST(10,"some text",0.25,FALSE) = #VALUE!