POISSON.DIST

POISSON.DIST(x, mean, cumulative)

Returns the probability distribution function OR the cumulative probability function for a poisson distribution.

x	The number of events.
mean	The expected numeric value.
cumulative	A logical value indicating the type of function to use: False (or 0) = individual probability (equal to) True (<> 0) = cumulative probability (equal to or less than)

REMARKS

* For an illustrated example refer to the page under Distributions
* The poisson distribution is a discrete distribution
* The poisson distribution is used when events occur at random.
* If "cumulative" = False, then the height of the curve at "x" is returned.
* If "cumulative" = True, then the area under the curve to the left of "x" is returned.
* You can use the BINOM.DIST function to return the probability of getting a specific number of successes using a binomial distribution.
* This function was added in Excel 2010 to replace the POISSON function.
* For the Microsoft documentation refer to support.microsoft.com

	A
1	=POISSON.DIST(2, 5, FALSE) = 0.084
2	=POISSON.DIST(2, 5, TRUE) = 0.125
3	=POISSON.DIST(2, 2, 1) = 0.677
4	=POISSON.DIST(-2, 2, 1) = #NUM!