org.statcato.statistics.inferential
Class GoodnessOfFitTest

java.lang.Object
  extended by org.statcato.statistics.inferential.GoodnessOfFitTest

public class GoodnessOfFitTest
extends java.lang.Object

A Chi-square goodness-of-fit test.

Since:
1.0
Version:
%I%, %G%
Author:
Margaret Yau

Constructor Summary
GoodnessOfFitTest(int k, double confidence)
          Constructor.
 
Method Summary
 double criticalValue()
          Returns the critical value corresponding to the significance level and degrees of freedom.
 int DOF()
          Returns the degrees of freedom.
 double pValue(double ts)
          Returns the p-Value corresponding to the given test statistic in a chi-square distribution.
 double testStatistic(java.util.Vector<java.lang.Double> observedFreq, java.util.Vector<java.lang.Double> expectedFreq)
          Computes the chi-square test statistic for goodness-of-fit test in multinomial experiment, given the observed and expected frequencies.
 java.util.Vector<java.lang.Double> testStatisticContribution(java.util.Vector<java.lang.Double> observedFreq, java.util.Vector<java.lang.Double> expectedFreq)
          Returns a vector of each observed frequency's contribution to the chi-square test statistic.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

GoodnessOfFitTest

public GoodnessOfFitTest(int k,
                         double confidence)
Constructor.

Parameters:
k - number of categories
confidence - confidence level
Method Detail

testStatisticContribution

public java.util.Vector<java.lang.Double> testStatisticContribution(java.util.Vector<java.lang.Double> observedFreq,
                                                                    java.util.Vector<java.lang.Double> expectedFreq)
Returns a vector of each observed frequency's contribution to the chi-square test statistic.

Parameters:
observedFreq - vector of observed frequencies
expectedFreq - vector of expected frequencies
Returns:
a vector of Double (each observed frequency's contribution to test statistic)

testStatistic

public double testStatistic(java.util.Vector<java.lang.Double> observedFreq,
                            java.util.Vector<java.lang.Double> expectedFreq)
Computes the chi-square test statistic for goodness-of-fit test in multinomial experiment, given the observed and expected frequencies. Chi^2 = Sum_{(O - E)^2 / E}.

Parameters:
observedFreq - a vector of observed frequencies
expectedFreq - a vector of expected frequencies
Returns:
test statistic

DOF

public int DOF()
Returns the degrees of freedom.

Returns:
degrees of freedom

criticalValue

public double criticalValue()
Returns the critical value corresponding to the significance level and degrees of freedom.

Returns:
critical value

pValue

public double pValue(double ts)
Returns the p-Value corresponding to the given test statistic in a chi-square distribution.

Parameters:
ts -
Returns:
p-value