public abstract class

Statistics

extends Object
java.lang.Object
   ↳ org.jfree.data.statistics.Statistics

Class Overview

A utility class that provides some common statistical functions.

Summary

Public Constructors
Statistics()
Public Methods
static double calculateMean(Number[] values)
Returns the mean of an array of numbers.
static double calculateMean(Collection values, boolean includeNullAndNaN)
Returns the mean of a collection of Number objects.
static double calculateMean(Number[] values, boolean includeNullAndNaN)
Returns the mean of an array of numbers.
static double calculateMean(Collection values)
Returns the mean of a collection of Number objects.
static double calculateMedian(List values, boolean copyAndSort)
Calculates the median for a list of values (Number objects).
static double calculateMedian(List values, int start, int end)
Calculates the median for a sublist within a list of values (Number objects).
static double calculateMedian(List values, int start, int end, boolean copyAndSort)
Calculates the median for a sublist within a list of values (Number objects).
static double calculateMedian(List values)
Calculates the median for a list of values (Number objects).
static double getCorrelation(Number[] data1, Number[] data2)
Calculates the correlation between two datasets.
static double[] getLinearFit(Number[] xData, Number[] yData)
Fits a straight line to a set of (x, y) data, returning the slope and intercept.
static double[][] getMovingAverage(Number[] xData, Number[] yData, int period)
Returns a data set for a moving average on the data set passed in.
static double getSlope(Number[] xData, Number[] yData)
Finds the slope of a regression line using least squares.
static double getStdDev(Number[] data)
Returns the standard deviation of a set of numbers.
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public Statistics ()

Public Methods

public static double calculateMean (Number[] values)

Returns the mean of an array of numbers. This is equivalent to calling calculateMean(values, true).

Parameters
values the values (null not permitted).
Returns
  • The mean.

public static double calculateMean (Collection values, boolean includeNullAndNaN)

Returns the mean of a collection of Number objects.

Parameters
values the values (null not permitted).
includeNullAndNaN a flag that controls whether or not null and Double.NaN values are included in the calculation (if either is present in the array, the result is NaN).
Returns
  • The mean.

public static double calculateMean (Number[] values, boolean includeNullAndNaN)

Returns the mean of an array of numbers.

Parameters
values the values (null not permitted).
includeNullAndNaN a flag that controls whether or not null and Double.NaN values are included in the calculation (if either is present in the array, the result is NaN).
Returns
  • The mean.

public static double calculateMean (Collection values)

Returns the mean of a collection of Number objects.

Parameters
values the values (null not permitted).
Returns
  • The mean.

public static double calculateMedian (List values, boolean copyAndSort)

Calculates the median for a list of values (Number objects). If copyAndSort is false, the list is assumed to be presorted in ascending order by value.

Parameters
values the values (null permitted).
copyAndSort a flag that controls whether the list of values is copied and sorted.
Returns
  • The median.

public static double calculateMedian (List values, int start, int end)

Calculates the median for a sublist within a list of values (Number objects).

Parameters
values the values, in any order (null not permitted).
start the start index.
end the end index.
Returns
  • The median.

public static double calculateMedian (List values, int start, int end, boolean copyAndSort)

Calculates the median for a sublist within a list of values (Number objects). The entire list will be sorted if the ascendingfalse.

Parameters
values the values (null not permitted).
start the start index.
end the end index.
copyAndSort a flag that that controls whether the list of values is copied and sorted.
Returns
  • The median.

public static double calculateMedian (List values)

Calculates the median for a list of values (Number objects). The list of values will be copied, and the copy sorted, before calculating the median. To avoid this step (if your list of values is already sorted), use the calculateMedian(List, boolean) method.

Parameters
values the values (null permitted).
Returns
  • The median.

public static double getCorrelation (Number[] data1, Number[] data2)

Calculates the correlation between two datasets. Both arrays should contain the same number of items. Null values are treated as zero.

Information about the correlation calculation was obtained from: http://trochim.human.cornell.edu/kb/statcorr.htm

Parameters
data1 the first dataset.
data2 the second dataset.
Returns
  • The correlation.

public static double[] getLinearFit (Number[] xData, Number[] yData)

Fits a straight line to a set of (x, y) data, returning the slope and intercept.

Parameters
xData the x-data (null not permitted).
yData the y-data (null not permitted).
Returns
  • A double array with the intercept in [0] and the slope in [1].

public static double[][] getMovingAverage (Number[] xData, Number[] yData, int period)

Returns a data set for a moving average on the data set passed in.

Parameters
xData an array of the x data.
yData an array of the y data.
period the number of data points to average
Returns
  • A double[][] the length of the data set in the first dimension, with two doubles for x and y in the second dimension

public static double getSlope (Number[] xData, Number[] yData)

Finds the slope of a regression line using least squares.

Parameters
xData the x-values (null not permitted).
yData the y-values (null not permitted).
Returns
  • The slope.

public static double getStdDev (Number[] data)

Returns the standard deviation of a set of numbers.

Parameters
data the data (null or zero length array not permitted).
Returns
  • The standard deviation of a set of numbers.