org.statcato.statistics.inferential
Class HypothesisTest1Var

java.lang.Object
  extended by org.statcato.statistics.inferential.HypothesisTest1Var

public class HypothesisTest1Var
extends java.lang.Object

A hypothesis test for 1 population variance

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

Constructor Summary
HypothesisTest1Var(int n, double sigma2, double confidenceLevel, int testType)
          Constructor.
 
Method Summary
 java.lang.String criticalValue()
          Returns the critical value corresponding to the given confidence level and type of test.
 double pValue(double s2)
          Returns the p-value corresponding to s2 in a chi-square distribution.
 double testStatistics(double s2)
          Returns the test statistics for the given sample variance s2.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

HypothesisTest1Var

public HypothesisTest1Var(int n,
                          double sigma2,
                          double confidenceLevel,
                          int testType)
Constructor.

Parameters:
n - sample size
sigma2 - hypothesized variance
confidenceLevel - confidence level
testType - (as defined in HypothesisTest)
Method Detail

testStatistics

public double testStatistics(double s2)
Returns the test statistics for the given sample variance s2.

X2 = (n-1)^2 * s2 / sigma2

Parameters:
s2 - hypothesized population variance
Returns:
test statistic X2 (chi-square)

criticalValue

public java.lang.String criticalValue()
Returns the critical value corresponding to the given confidence level and type of test. Uses the chi-square distribution.

Returns:
critical value
See Also:
HypothesisTest

pValue

public double pValue(double s2)
Returns the p-value corresponding to s2 in a chi-square distribution.

Parameters:
s2 - variance
Returns:
p-value