# Documentation/Calc Functions/POISSON.DIST

POISSON.DIST

## Category:

Statistical Analysis

## Summary:

Calculates either a probability mass function or a cumulative distribution function of the Poisson distribution for a given value.

## Syntax:

POISSON.DIST(Number; Mean; C)

## Returns:

Returns a real number which is either a probability mass function or a cumulative distribution function of the Poisson distribution for Number with mean value as Mean.

## Arguments:

Number is a real number or a reference to the cell containing that number which represents the value based on which the Poisson distribution is calculated.

Mean is a real number or a reference to the cell containing that number which represents the middle value of the Poisson distribution.

C can be 0 or False to calculate the probability mass function. It can be any other value or True to calculate the cumulative distribution function.

• If Number is a non-integer value then the function uses its floor value, i.e. it is truncated to an integer. However, if the Number is less than 0 then the function returns an error value.
• If Mean is less than 0 then the function returns an error value.

• The formula for POISSON.DIST is:

If C is FALSE(), POISSON.DIST returns the probability mass function value:

If C is TRUE(), POISSON.DIST returns the cumulative distribution function value:

where x is Number

• For more details on Poisson distribution, visit Wikipedia

## Examples:

Formula Description Returns
=POISSON.DIST(8;4.5;1) The function calculates the cumulative distribution function for the poisson distribution. 0.959742687517962
=POISSON.DIST(8;4.5;0) The function calculates the probability mass function for the poisson distribution. 0.046329159165318
=POISSON.DIST(-11.2;4.5;0) The function returns an error value since the Number is negative. Err:502
=POISSON.DIST(11.2;-4.5;0) The function returns an error value since the Mean is negative. Err:502

None

POISSON.DIST