# POISSON Function

The POISSON function is one of the statistical functions. It is used to return the Poisson distribution.

The POISSON function syntax is:

POISSON(x, mean, cumulative-flag)

where

x is the number of events, a numeric value greater than 0.

mean is the expected numeric value greater than 0.

cumulative-flag is the form of the function, a logical value: TRUE or FALSE. If cumulative-flag is TRUE, the function will return the cumulative Poisson probability; if FALSE, it will return the Poisson probability mass function.

The values can be entered manually or included into the cell you make reference to.

To apply the POISSON function,

1. select the cell where you wish to display the result,
2. click the Insert function icon situated at the top toolbar,
   or right-click within a selected cell and select the Insert Function option from the menu,
   or click the icon situated at the formula bar,
3. select the Statistical function group from the list,
4. click the POISSON function,
5. enter the required arguments separating them by commas,
6. press the Enter button.

The result will be displayed in the selected cell.