sdsu.algorithms.data
Class Bernoulli

java.lang.Object
  |
  +--sdsu.algorithms.data.ProbabilityDistribution
        |
        +--sdsu.algorithms.data.DiscreteProbability
              |
              +--sdsu.algorithms.data.Bernoulli

Direct Known Subclasses:

Geometric

public class Bernoulli

extends DiscreteProbability

A Bernoulli distribution is defined on a sample space of two events. For example: tossing a coin, did I get heads?; Throwing a die, did I get die side 5?. This class labels the two items in the sample space as 0 (failure) and 1 (success). Giving the probability of the success event (1) also determince the probability of failure. This class is adapted from Smalltalk-80: The language and Its Implementation, Goldberg & Robson, Addison-Wesley, 1983, chapter 21, pages 417-438.

Version:

1.0 10 June 1997

Author:

Roger Whitney (whitney@cs.sdsu.edu)

Constructor Summary

Bernoulli(double successProbability)
Returns a Bernoulli with the propability of success equal to successProbability.

Method Summary

double	density(double sampleSpaceItem) Returns the probability of an item in the sample space will occur.
double	mean() Returns the mean of the Bernoulli distribution
double	nextElement() Returns 1 or 0.
double	variance() Returns the variance of the probability distribution

Methods inherited from class sdsu.algorithms.data.DiscreteProbability

distribution

Methods inherited from class sdsu.algorithms.data.ProbabilityDistribution

density

Methods inherited from class java.lang.Object

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

Constructor Detail

Bernoulli

public Bernoulli(double successProbability)
          throws OutOfBoundsException

Returns a Bernoulli with the propability of success equal to successProbability.

Throws:

OutOfBoundsException - thrown if successProbability is not between 0 and 1.

Method Detail

density

public double density(double sampleSpaceItem)
               throws OutOfBoundsException

Returns the probability of an item in the sample space will occur. sampleSpaceItem must be either 0 or 1.

Parameters:

sampleSpaceItem - item in the sample space for which the probability of occuring is computed.

Throws:

OutOfBoundsException - thrown if sampleSpaceItem is not either 0 or 1.

Overrides:

density in class ProbabilityDistribution

mean

public double mean()

Returns the mean of the Bernoulli distribution

Overrides:

mean in class ProbabilityDistribution

variance

public double variance()

Returns the variance of the probability distribution

Overrides:

variance in class ProbabilityDistribution

nextElement

public double nextElement()

Returns 1 or 0. 1 is returned with the probability of success, set in the constructor.

Overrides:

nextElement in class ProbabilityDistribution