Excel like a finance pro.
Statistical function
NEGBINOM.DIST
Returns the negative binomial distribution: the probability of a number of failures before a given number of successes.
When to use it
The negative binomial distribution: the probability of a number of failures before a target number of successes. Also used for over-dispersed counts.
The shape of it
- Syntax
=NEGBINOM.DIST(number_f, number_s, probability_s, cumulative)
Worked examples
Exactly ten failures
=NEGBINOM.DIST(10,5,0.25,FALSE) → 0.0550487
Exactly 10 failures before the 5th success at a 25% success rate.
Ten or fewer
=NEGBINOM.DIST(10,5,0.25,TRUE) → 0.3135141
Ten or fewer failures.
First try
=NEGBINOM.DIST(0,1,0.5,FALSE) → 0.5
Success on the first try at 50%.
Worth knowing
- Sales calls until the third yes: failures before 3 successes.
- Use it for counts whose variance exceeds the mean, where Poisson underfits.
- Introduced with the cumulative flag in Excel 2010.
Where it goes wrong
- #NUM! when p is outside 0 to 1 or counts are negative.
- Non-integers are truncated.
Related
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