Package org.apache.commons.math.distribution

Interface PoissonDistribution

All Superinterfaces:

DiscreteDistribution, Distribution, IntegerDistribution

All Known Implementing Classes:

PoissonDistributionImpl

public interface PoissonDistribution
extends IntegerDistribution

Interface representing the Poisson Distribution.

References:

• Poisson distribution

Method Summary

Modifier and Type	Method	Description
double	getMean()	Get the mean for the distribution.
double	normalApproximateProbability(int x)	Calculates the Poisson distribution function using a normal approximation.
void	setMean(double p)	Deprecated. as of v2.1

Methods inherited from interface org.apache.commons.math.distribution.DiscreteDistribution

probability

Methods inherited from interface org.apache.commons.math.distribution.Distribution

cumulativeProbability, cumulativeProbability

Methods inherited from interface org.apache.commons.math.distribution.IntegerDistribution

cumulativeProbability, cumulativeProbability, inverseCumulativeProbability, probability

Method Detail

getMean

double getMean()

Get the mean for the distribution.

Returns:

the mean for the distribution.

setMean

@Deprecated
void setMean(double p)

Deprecated.

as of v2.1

Set the mean for the distribution. The parameter value must be positive; otherwise an IllegalArgument is thrown.

Parameters:

p - the mean

Throws:

java.lang.IllegalArgumentException - if p ≤ 0

normalApproximateProbability

double normalApproximateProbability(int x)
                             throws MathException

Calculates the Poisson distribution function using a normal approximation.

Parameters:

x - the upper bound, inclusive

Returns:

the distribution function value calculated using a normal approximation

Throws:

MathException - if an error occurs computing the normal approximation