Overview Package Class Use Tree Index Deprecated About
Prev Class | Next ClassFrames | No Frames
Summary: Nested | Field | Method | ConstrDetail: Nested | Field | Method | Constr

net.sourceforge.jiu.util

Class Statistics

public class Statistics
extends java.lang.Object
A number of static methods to compute statistical properties of an array of double values. Implements the computation of mean, variance and standard deviation for double values.
Author:
Marco Schmidt
Since:
0.11.0

Constructor Summary

Statistics()

Method Summary

static double
computeMean(double[] values)
Computes the mean value for the argument array.
static double
computeMean(double[] values, int offset, int number)
Computes the mean value for some elements of the argument array.
static double
computeStandardDeviation(double[] values)
Computes the standard deviation for the argument array of values.
static double
computeStandardDeviation(double[] values, double mean)
Computes the standard deviation for the argument array of values.
static double
computeStandardDeviation(double[] values, int offset, int number)
Computes the standard deviation for some of the argument array's values.
static double
computeStandardDeviation(double[] values, int offset, int number, double mean)
Computes the standard deviation for some of the argument array's values.
static double
computeVariance(double[] values)
Computes the variance for the argument array.
static double
computeVariance(double[] values, double mean)
Computes the variance for some of the argument array's values.
static double
computeVariance(double[] values, int offset, int number)
Computes the variance for some of the argument array's values.
static double
computeVariance(double[] values, int offset, int number, double mean)
Computes the variance for some of the argument array's values.

Constructor Details

Statistics

private Statistics()

Method Details

computeMean

public static double computeMean(double[] values)
Computes the mean value for the argument array. Adds all values and divides them by the number of array elements.
Parameters:
values - double array on which the mean is to be determined
Returns:
computed mean value

computeMean

public static double computeMean(double[] values,
                                 int offset,
                                 int number)
Computes the mean value for some elements of the argument array. Adds all values and divides them by the number of array elements.
Parameters:
values - array from which elements are read
offset - index of the first element to be used
number - number of elements to be used
Returns:
computed mean value

computeStandardDeviation

public static double computeStandardDeviation(double[] values)
Computes the standard deviation for the argument array of values.
Parameters:
values - array from which elements are read
Returns:
computed standard deviation

computeStandardDeviation

public static double computeStandardDeviation(double[] values,
                                              double mean)
Computes the standard deviation for the argument array of values. Reuses the mean value for that argument which must have been computed before.
Parameters:
values - array from which elements are read
mean - the mean value for the array, possibly computed with a call to computeMean(double[]).
Returns:
computed standard deviation

computeStandardDeviation

public static double computeStandardDeviation(double[] values,
                                              int offset,
                                              int number)
Computes the standard deviation for some of the argument array's values. If you already have computed a mean value using computeMean(double[],int,int), better call computeStandardDeviation(double[],int,int,double). Otherwise, this method has to compute mean again.
Parameters:
values - array from which elements are read
offset - first element to be used
number - number of elements used starting at values[offset]
Returns:
computed standard deviation

computeStandardDeviation

public static double computeStandardDeviation(double[] values,
                                              int offset,
                                              int number,
                                              double mean)
Computes the standard deviation for some of the argument array's values. Use this version of the method if you already have a mean value, otherwise this method must be computed again.
Parameters:
values - array from which elements are read
offset - first element to be used
number - number of elements used starting at values[offset]
mean - value of the elements
Returns:
computed standard deviation

computeVariance

public static double computeVariance(double[] values)
Computes the variance for the argument array.
Parameters:
values - array from which elements are read
Returns:
variance for the array elements

computeVariance

public static double computeVariance(double[] values,
                                     double mean)
Computes the variance for some of the argument array's values.
Parameters:
values - array from which elements are read
mean - the mean for the array elements
Returns:
variance for the array elements

computeVariance

public static double computeVariance(double[] values,
                                     int offset,
                                     int number)
Computes the variance for some of the argument array's values. If you already have computed a mean value using computeMean(double[],int,int), better call computeVariance(double[],int,int,double). Otherwise, this method has to compute mean again.
Parameters:
values - array from which elements are read
offset - first element to be used
number - number of elements used starting at values[offset]
Returns:
computed variance

computeVariance

public static double computeVariance(double[] values,
                                     int offset,
                                     int number,
                                     double mean)
Computes the variance for some of the argument array's values. Use this version of the method in case mean has already been computed.
Parameters:
values - array from which elements are read
offset - first element to be used
number - number of elements used starting at values[offset]
mean - the mean for the array elements
Returns:
computed variance

Overview Package Class Use Tree Index Deprecated About