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

java.lang.Object
  net.sf.doodleproject.numerics4j.statistics.distribution.ContinuousDistribution
      net.sf.doodleproject.numerics4j.statistics.distribution.FDistribution

All Implemented Interfaces:

Distribution

public class FDistribution
extends ContinuousDistribution

The F distribution (1).

References:

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

Version:

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

Constructor Summary

FDistribution()
Default constructor.

FDistribution(double dfn, double dfd)
Create a distribution with the given numerator degrees of freedom and denominator degrees of freedom.

Method Summary

double	cumulativeProbability(double x) The CDF for this distribution.
double	getDenominatorDegreesOfFreedom() Access the denominator degrees of freedom.
double	getNumeratorDegreesOfFreedom() Access the numerator degrees of freedom.
double	inverseCumulativeProbability(double p) The inverse CDF for this distribution.
void	setDenominatorDegreesOfFreedom(double degreesOfFreedom) Modify the denominator degrees of freedom.
void	setNumeratorDegreesOfFreedom(double degreesOfFreedom) Modify the numerator degrees of freedom.

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

findInverseCumulativeProbability

Methods inherited from class java.lang.Object

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

Constructor Detail

FDistribution

public FDistribution()

Default constructor. Numerator degrees of freedom and denominator degrees of freedom are both set to 1.

FDistribution

public FDistribution(double dfn,
                     double dfd)

Create a distribution with the given numerator degrees of freedom and denominator degrees of freedom.

Parameters:

dfn - the numerator degrees of freedom.

dfd - the denominator degrees of freedom.

Method Detail

cumulativeProbability

public double cumulativeProbability(double x)
                             throws NumericException

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

Specified by:

cumulativeProbability in class ContinuousDistribution

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.

getDenominatorDegreesOfFreedom

public double getDenominatorDegreesOfFreedom()

Access the denominator degrees of freedom.

Returns:

the denominator degrees of freedom.

getNumeratorDegreesOfFreedom

public double getNumeratorDegreesOfFreedom()

Access the numerator degrees of freedom.

Returns:

the numerator degrees of freedom.

inverseCumulativeProbability

public double inverseCumulativeProbability(double p)
                                    throws NumericException

The inverse CDF for this distribution. This method returns x such that, P(X < x) = p.

Specified by:

inverseCumulativeProbability in class ContinuousDistribution

Parameters:

p - the cumulative probability.

Returns:

x

Throws:

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

setDenominatorDegreesOfFreedom

public void setDenominatorDegreesOfFreedom(double degreesOfFreedom)

Modify the denominator degrees of freedom.

Parameters:

degreesOfFreedom - the new denominator degrees of freedom.

setNumeratorDegreesOfFreedom

public void setNumeratorDegreesOfFreedom(double degreesOfFreedom)

Modify the numerator degrees of freedom.

Parameters:

degreesOfFreedom - the new numerator degrees of freedom.