PoissonInv() returns the inverse of the accumulated probability of the Poisson distribution.
Syntax:
PoissonInv(prob, mean)
Return data type: number
| Argument | Description | 
|---|---|
| prob | A probability associated with the Poisson-probability distribution. It must be a number between 0 and 1. | 
| mean | A positive number defining the average outcome. | 
This function is related 
				to the PoissonDIST function in the following way: 
If prob = PoissonDist(value, mean), then PoissonInv(prob, mean) = value