Poisson distribution

Returns the Poisson distribution of a random variable. This function predicts the number of identified events to take place over a specified period. For example, it can predict the number of cars to arrive at a toll plaza in a one-minute interval.

Syntax

PoissonDistribution <Cumulative> (x, lambda)

Where:

x is the number of events in the prediction.

lambda is the expected numeric value of the expression.

Cumulative is a logical value that determines the form of the probability distribution returned:

• If Cumulative = 0 (default), the function returns the probability that the number of random events will be between 0 and x.
• If Cumulative = 1, the function returns the probability that the number of random events will be exactly x.

Expression

For type = 1:

For type = 0:

Usage Notes

If x is not an integer, it is truncated.

The following conditions are invalid:

• x or lambda is nonnumeric
• x < 0
• lambda £ 0