# PoissonDist Script and chart function

`PoissonDist()` returns the accumulated probability of the Poisson distribution.

Syntax:

PoissonDist(value, mean)

Return data type: number

Arguments

| Argument | Description |
| --- | --- |
| `value` | The value at which you want to evaluate the distribution. The value must not be negative. |
| `mean` | A positive number defining the average outcome. |

This function is related to the `PoissonInv` function in the following way:   
`If prob = PoissonDist(value, mean), then PoissonInv(prob, mean) = value`