WorksheetFunction.Poisson(Double, Double, Boolean) Method
Definition
Important
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Returns the Poisson distribution. A common application of the Poisson distribution is predicting the number of events over a specific time, such as the number of cars arriving at a toll plaza in 1 minute.
public:
double Poisson(double Arg1, double Arg2, bool Arg3);public double Poisson (double Arg1, double Arg2, bool Arg3);Public Function Poisson (Arg1 As Double, Arg2 As Double, Arg3 As Boolean) As DoubleParameters
- Arg1
- Double
X - the number of events.
- Arg2
- Double
Mean - the expected numeric value.
- Arg3
- Boolean
Cumulative - a logical value that determines the form of the probability distribution returned. If cumulative is TRUE, POISSON returns the cumulative Poisson probability that the number of random events occurring will be between zero and x inclusive; if FALSE, it returns the Poisson probability mass function that the number of events occurring will be exactly x.
Returns
Remarks
Important: This function has been replaced with one or more new functions that may provide improved accuracy and whose names better reflect their usage. This function is still available for compatibility with earlier versions of Excel. However, if backward compatibility is not required, you should consider using the new functions from now on, because they more accurately describe their functionality. For more information about the new function, see the Poisson_Dist(Double, Double, Boolean) method.
If x is not an integer, it is truncated.
If x or mean is nonnumeric, Poisson returns the #VALUE! error value.
If x < 0, Poisson returns the #NUM! error value.
If mean ≤ 0, Poisson returns the #NUM! error value.
Poisson is calculated as follows.
For cumulative = false:
Figure 1: Calcuation when cumulative is false
For cumulative = true:
Figure 2: Calcuation when cumulative is true