org.apache.commons.math.distribution
Interface Distribution

All Known Subinterfaces:

BinomialDistribution, ChiSquaredDistribution, ContinuousDistribution, DiscreteDistribution, ExponentialDistribution, FDistribution, GammaDistribution, HypergeometricDistribution, IntegerDistribution, NormalDistribution, PoissonDistribution, TDistribution

All Known Implementing Classes:

AbstractContinuousDistribution, AbstractDistribution, AbstractIntegerDistribution, BinomialDistributionImpl, ChiSquaredDistributionImpl, ExponentialDistributionImpl, FDistributionImpl, GammaDistributionImpl, HypergeometricDistributionImpl, NormalDistributionImpl, PoissonDistributionImpl, TDistributionImpl

public interface Distribution

Base interface for probability distributions.

Version:

$Revision: 1.2 $ $Date: 2004/11/07 20:39:15 $

Method Summary

double	cumulativeProbability(double x) For a random variable X whose values are distributed according to this distribution, this method returns P(X ≤ x).
double	cumulativeProbability(double x0, double x1) For a random variable X whose values are distributed according to this distribution, this method returns P(x0 ≤ X ≤ x1).

Method Detail

cumulativeProbability

public double cumulativeProbability(double x)
                             throws MathException

For a random variable X whose values are distributed according to this distribution, this method returns P(X ≤ x). In other words, this method represents the (cumulative) distribution function, or CDF, for this distribution.

Parameters:

x - the value at which the distribution function is evaluated.

Returns:

the probability that a random variable with this distribution takes a value less than or equal to x

Throws:

MathException - if the cumulative probability can not be computed due to convergence or other numerical errors.

cumulativeProbability

public double cumulativeProbability(double x0,
                                    double x1)
                             throws MathException

For a random variable X whose values are distributed according to this distribution, this method returns P(x0 ≤ X ≤ x1).

Parameters:

x0 - the (inclusive) lower bound

x1 - the (inclusive) upper bound

Returns:

the probability that a random variable with this distribution will take a value between x0 and x1, including the endpoints

Throws:

MathException - if the cumulative probability can not be computed due to convergence or other numerical errors.

IllegalArgumentException - if x0 > x1