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

java.lang.Object
  extended by net.sf.doodleproject.numerics4j.statistics.distribution.ContinuousDistribution
      extended by net.sf.doodleproject.numerics4j.statistics.distribution.NormalDistribution
All Implemented Interfaces:
Distribution

public class NormalDistribution
extends ContinuousDistribution

The Normal distribution (1).

References:

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

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

Constructor Summary
NormalDistribution()
          Default constructor.
NormalDistribution(double m, double s)
          Create a distribution with the given mean and standard deviation.
 
Method Summary
 double cumulativeProbability(double x)
          The CDF for this distribution.
 double getMean()
          Access the mean.
 double getStandardDeviation()
          Access the standard deviation.
 double inverseCumulativeProbability(double p)
          The inverse CDF for this distribution.
 void setMean(double m)
          Modify the mean.
 void setStandardDeviation(double std)
          Modify the standard deviation.
 
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

NormalDistribution

public NormalDistribution()
Default constructor. Mean is set to zero and standard deviation is set to one.


NormalDistribution

public NormalDistribution(double m,
                          double s)
Create a distribution with the given mean and standard deviation.

Parameters:
m - the mean.
s - the standard deviation.
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.

getMean

public double getMean()
Access the mean.

Returns:
the mean.

getStandardDeviation

public double getStandardDeviation()
Access the standard deviation.

Returns:
the standard deviation.

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.

setMean

public void setMean(double m)
Modify the mean.

Parameters:
m - the new mean value.

setStandardDeviation

public void setStandardDeviation(double std)
Modify the standard deviation.

Parameters:
std - The new standard deviation value.


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