net.sf.doodleproject.numerics4j.statistics.distribution
Class HypergeometricDistribution

java.lang.Object
  net.sf.doodleproject.numerics4j.statistics.distribution.DiscreteDistribution
      net.sf.doodleproject.numerics4j.statistics.distribution.HypergeometricDistribution

All Implemented Interfaces:

Distribution

public class HypergeometricDistribution
extends DiscreteDistribution

The Hypergeometric distribution.

References:

1. Eric W. Weisstein. "Hypergeometric Distribution." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/HypergeometricDistribution.html

Since:

1.2

Version:

$Revision: 1.2 $ $Date: 2007/10/25 04:44:10 $

Constructor Summary

HypergeometricDistribution()
Default constructor.

HypergeometricDistribution(int successes, int failures, int sample)
Create a distribution with the given number of failures, number of successes, and sample size.

Method Summary

double	cumulativeProbability(int x) The CDF for this distribution.
int	getNumberOfFailures() Access the number of failures.
int	getNumberOfSuccesses() Access the number of successes.
int	getSampleSize() Access the sample size.
int	inverseCumulativeProbability(double p) The inverse CDF for this distribution.
double	probability(int x) The PMF for this distribution.
void	setNumberOfFailures(int n) Modify the number of failures.
void	setNumberOfSuccesses(int n) Modify the number of successes.
void	setSampleSize(int n) Modify the sample size.

Methods inherited from class net.sf.doodleproject.numerics4j.statistics.distribution.DiscreteDistribution

findInverseCumulativeProbability, simpleCumulativeProbability

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

HypergeometricDistribution

public HypergeometricDistribution()

Default constructor. The number of failures, number of successes, and sample size are all set to one.

HypergeometricDistribution

public HypergeometricDistribution(int successes,
                                  int failures,
                                  int sample)

Create a distribution with the given number of failures, number of successes, and sample size.

Parameters:

successes - the number of successes.

failures - the number of failures.

sample - the sample size.

Method Detail

cumulativeProbability

public double cumulativeProbability(int x)
                             throws NumericException

The CDF for this distribution. This method returns P(X ≤ x).

Specified by:

cumulativeProbability in class DiscreteDistribution

Parameters:

x - the value at which the CDF is evaluated.

Returns:

CDF for this distribution.

Throws:

NumericException - if the cumulative probability can not be computed.

getNumberOfFailures

public int getNumberOfFailures()

Access the number of failures.

Returns:

the number of failures.

getNumberOfSuccesses

public int getNumberOfSuccesses()

Access the number of successes.

Returns:

the number of successes.

getSampleSize

public int getSampleSize()

Access the sample size.

Returns:

the sample size.

inverseCumulativeProbability

public int inverseCumulativeProbability(double p)
                                 throws NumericException

The inverse CDF for this distribution. This method returns the largest x such that, P(X ≤ x) ≤ p. The return value must also satisfy P(X ≥ x) &ge 1 - p.

Specified by:

inverseCumulativeProbability in class DiscreteDistribution

Parameters:

p - the cumulative probability.

Returns:

x

Throws:

NumericException - if the inverse cumulative probability can not be computed.

probability

public double probability(int x)

The PMF for this distribution. This method returns P(X = x).

Specified by:

probability in class DiscreteDistribution

Parameters:

x - the value at which the probability is evaluated.

Returns:

PMF for this distribution.

setNumberOfFailures

public void setNumberOfFailures(int n)

Modify the number of failures.

Parameters:

n - the new number of failures value.

setNumberOfSuccesses

public void setNumberOfSuccesses(int n)

Modify the number of successes.

Parameters:

n - the new number of successes value.

setSampleSize

public void setSampleSize(int n)

Modify the sample size.

Parameters:

n - the new sample size value.