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

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

All Implemented Interfaces:

Distribution

public class BinomialDistribution
extends DiscreteDistribution

The Binomial distribution.

References:

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

Since:

1.2

Version:

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

Constructor Summary

BinomialDistribution()
Default constructor.

BinomialDistribution(int n, double p)
Create a distribution with the given number of trials and probability of success.

Method Summary

double	cumulativeProbability(int x) The CDF for this distribution.
int	getNumberOfTrials() Access the number of trials.
double	getProbabilityOfSuccess() Access probability of success.
int	inverseCumulativeProbability(double p) The inverse CDF for this distribution.
double	probability(int x) The PMF for this distribution.
void	setNumberOfTrials(int n) Modify the number of trials.
void	setProbabilityOfSuccess(double p) Modify probability of success.

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

BinomialDistribution

public BinomialDistribution()

Default constructor. Number of trials is set to one and probability of success is set to 0.5.

BinomialDistribution

public BinomialDistribution(int n,
                            double p)

Create a distribution with the given number of trials and probability of success.

Parameters:

n - the number of trials.

p - the probability of success.

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.

getNumberOfTrials

public int getNumberOfTrials()

Access the number of trials.

Returns:

the number of trials.

getProbabilityOfSuccess

public double getProbabilityOfSuccess()

Access probability of success.

Returns:

the probability of success.

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.

setNumberOfTrials

public void setNumberOfTrials(int n)

Modify the number of trials.

Parameters:

n - the new number of trials value.

setProbabilityOfSuccess

public void setProbabilityOfSuccess(double p)

Modify probability of success.

Parameters:

p - the new probability of success value.