weka.experiment
Class PairedStats

java.lang.Object
  extended by weka.experiment.PairedStats
All Implemented Interfaces:
RevisionHandler
Direct Known Subclasses:
PairedStatsCorrected

public class PairedStats
extends java.lang.Object
implements RevisionHandler

A class for storing stats on a paired comparison (t-test and correlation)

Version:
$Revision: 1.10 $
Author:
Len Trigg (trigg@cs.waikato.ac.nz)

Field Summary
 double correlation
          The correlation coefficient
 double count
          The number of data points seen
 double differencesProbability
          The probability of obtaining the observed differences
 int differencesSignificance
          A significance indicator: 0 if the differences are not significant > 0 if x significantly greater than y < 0 if x significantly less than y
 Stats differencesStats
          The stats associated with the paired differences
 double sigLevel
          The significance level for comparisons
 Stats xStats
          The stats associated with the data in column 1
 double xySum
          The sum of the products
 Stats yStats
          The stats associated with the data in column 2
 
Constructor Summary
PairedStats(double sig)
          Creates a new PairedStats object with the supplied significance level.
 
Method Summary
 void add(double[] value1, double[] value2)
          Adds an array of observed pair of values.
 void add(double value1, double value2)
          Add an observed pair of values.
 void calculateDerived()
          Calculates the derived statistics (significance etc).
 int getDegreesOfFreedom()
          Gets the degrees of freedom.
 java.lang.String getRevision()
          Returns the revision string.
static void main(java.lang.String[] args)
          Tests the paired stats object from the command line.
 void setDegreesOfFreedom(int d)
          Sets the degrees of freedom (if calibration is required).
 void subtract(double[] value1, double[] value2)
          Removes an array of observed pair of values.
 void subtract(double value1, double value2)
          Removes an observed pair of values.
 java.lang.String toString()
          Returns statistics on the paired comparison.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

xStats

public Stats xStats
The stats associated with the data in column 1


yStats

public Stats yStats
The stats associated with the data in column 2


differencesStats

public Stats differencesStats
The stats associated with the paired differences


differencesProbability

public double differencesProbability
The probability of obtaining the observed differences


correlation

public double correlation
The correlation coefficient


xySum

public double xySum
The sum of the products


count

public double count
The number of data points seen


differencesSignificance

public int differencesSignificance
A significance indicator: 0 if the differences are not significant > 0 if x significantly greater than y < 0 if x significantly less than y


sigLevel

public double sigLevel
The significance level for comparisons

Constructor Detail

PairedStats

public PairedStats(double sig)
Creates a new PairedStats object with the supplied significance level.

Parameters:
sig - the significance level for comparisons
Method Detail

setDegreesOfFreedom

public void setDegreesOfFreedom(int d)
Sets the degrees of freedom (if calibration is required).


getDegreesOfFreedom

public int getDegreesOfFreedom()
Gets the degrees of freedom.


add

public void add(double value1,
                double value2)
Add an observed pair of values.

Parameters:
value1 - the value from column 1
value2 - the value from column 2

subtract

public void subtract(double value1,
                     double value2)
Removes an observed pair of values.

Parameters:
value1 - the value from column 1
value2 - the value from column 2

add

public void add(double[] value1,
                double[] value2)
Adds an array of observed pair of values.

Parameters:
value1 - the array containing values from column 1
value2 - the array containing values from column 2

subtract

public void subtract(double[] value1,
                     double[] value2)
Removes an array of observed pair of values.

Parameters:
value1 - the array containing values from column 1
value2 - the array containing values from column 2

calculateDerived

public void calculateDerived()
Calculates the derived statistics (significance etc).


toString

public java.lang.String toString()
Returns statistics on the paired comparison.

Overrides:
toString in class java.lang.Object
Returns:
the t-test statistics as a string

getRevision

public java.lang.String getRevision()
Returns the revision string.

Specified by:
getRevision in interface RevisionHandler
Returns:
the revision

main

public static void main(java.lang.String[] args)
Tests the paired stats object from the command line. reads line from stdin, expecting two values per line.

Parameters:
args - ignored.