jstats
Class Mean

java.lang.Object
  jstats.Mean

public abstract class Mean

extends java.lang.Object

Static methods for calculating means and other measures of center.

Author:

Justin Scheiber, David Edelstein

Constructor Summary

Mean()

Method Summary

static double	arithmeticMean(double[] values) Calculate the arithmetic mean from an array of doubles.
static double	binomialMean(double probability, long trials) Calculate a binomial mean.
static double	geometricMean(double[] values) Calculates the geometic mean.
static double	grandMean(double[] weights, double[] means) Calculates the grand mean.
static double	harmonicMean(double[] values) Calculates a harmonic mean.
static double	hypergeometricMean(double n, double a, double b)
static double	median(double[] values) Computes a median of an array of values.
static double	midrange(double[] values) Computes the midrange (the value exactly between the lowest and highest values) from an array of doubles.
static double	probabilityMean(double probability, double[] values) Calculates the mean of a probability distribution.
static double	weightedMean(double[] weights, double[] values) Caculate a weighted mean.

Methods inherited from class java.lang.Object

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

Constructor Detail

Mean

public Mean()

Method Detail

median

public static double median(double[] values)
                     throws StatisticException

Computes a median of an array of values.

Parameters:

values - an array of doubles

Returns:

the median of the values array

Throws:

StatisticException - for an empty array

midrange

public static double midrange(double[] values)
                       throws StatisticException

Computes the midrange (the value exactly between the lowest and highest values) from an array of doubles.

Parameters:

values - an array of doubles

Returns:

the midrange of the values array

Throws:

StatisticException - for an empty array

arithmeticMean

public static double arithmeticMean(double[] values)
                             throws StatisticException

Calculate the arithmetic mean from an array of doubles.

Parameters:

values - An array of doubles.

Returns:

arithmetic mean

Throws:

StatisticException - for empty array

binomialMean

public static double binomialMean(double probability,
                                  long trials)
                           throws StatisticException

Calculate a binomial mean.

Parameters:

probability -

trials -

Returns:

the binomial mean

Throws:

StatisticException

geometricMean

public static double geometricMean(double[] values)
                            throws StatisticException

Calculates the geometic mean. Used to average ratios.

Parameters:

values - An array of doubles containing ratios.

Returns:

geometic mean

Throws:

StatisticException

grandMean

public static double grandMean(double[] weights,
                               double[] means)
                        throws StatisticException

Calculates the grand mean. Used to average multiple means with weights.

Parameters:

weights - An array of doubles containing weights that correspond to each of the means.

means - An array of doubles containing means from different observations.

Returns:

grand mean

Throws:

StatisticException

harmonicMean

public static double harmonicMean(double[] values)
                           throws StatisticException

Calculates a harmonic mean. Used to average frequencies.

Parameters:

values - An array of doubles containing frequencies.

Returns:

harmonic mean

Throws:

StatisticException

hypergeometricMean

public static double hypergeometricMean(double n,
                                        double a,
                                        double b)

probabilityMean

public static double probabilityMean(double probability,
                                     double[] values)
                              throws StatisticException

Calculates the mean of a probability distribution.

Parameters:

probability -

values -

Returns:

the mean of a probability distribution

Throws:

StatisticException

weightedMean

public static double weightedMean(double[] weights,
                                  double[] values)
                           throws StatisticException

Caculate a weighted mean. Used when the values in a set of data do not share equal importance.

Parameters:

weights - Weights to use when calculating the mean.

values - Data on which to perform the weighted mean.

Returns:

weighted mean

Throws:

StatisticException