Class WilcoxonSignedRankTest
 java.lang.Object

 org.apache.commons.math4.legacy.stat.inference.WilcoxonSignedRankTest

public class WilcoxonSignedRankTest extends Object
An implementation of the Wilcoxon signedrank test.


Constructor Summary
Constructors Constructor Description WilcoxonSignedRankTest()
Create a test instance where NaN's are left in place and ties get the average of applicable ranks.WilcoxonSignedRankTest(NaNStrategy nanStrategy, TiesStrategy tiesStrategy)
Create a test instance using the given strategies for NaN's and ties.

Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description double
wilcoxonSignedRank(double[] x, double[] y)
Computes the Wilcoxon signed ranked statistic comparing mean for two related samples or repeated measurements on a single sample.double
wilcoxonSignedRankTest(double[] x, double[] y, boolean exactPValue)
Returns the observed significance level, or pvalue, associated with a Wilcoxon signed ranked statistic comparing mean for two related samples or repeated measurements on a single sample.



Constructor Detail

WilcoxonSignedRankTest
public WilcoxonSignedRankTest()
Create a test instance where NaN's are left in place and ties get the average of applicable ranks. Use this unless you are very sure of what you are doing.

WilcoxonSignedRankTest
public WilcoxonSignedRankTest(NaNStrategy nanStrategy, TiesStrategy tiesStrategy)
Create a test instance using the given strategies for NaN's and ties. Only use this if you are sure of what you are doing. Parameters:
nanStrategy
 specifies the strategy that should be used for Double.NaN'stiesStrategy
 specifies the strategy that should be used for ties


Method Detail

wilcoxonSignedRank
public double wilcoxonSignedRank(double[] x, double[] y) throws NullArgumentException, NoDataException, DimensionMismatchException
Computes the Wilcoxon signed ranked statistic comparing mean for two related samples or repeated measurements on a single sample.This statistic can be used to perform a Wilcoxon signed ranked test evaluating the null hypothesis that the two related samples or repeated measurements on a single sample has equal mean.
Let X_{i} denote the i'th individual of the first sample and Y_{i} the related i'th individual in the second sample. Let Z_{i} = Y_{i}  X_{i}.
Preconditions:
 The differences Z_{i} must be independent.
 Each Z_{i} comes from a continuous population (they must be identical) and is symmetric about a common median.
 The values that X_{i} and Y_{i} represent are ordered, so the comparisons greater than, less than, and equal to are meaningful.
 Parameters:
x
 the first sampley
 the second sample Returns:
 wilcoxonSignedRank statistic (the larger of W+ and W)
 Throws:
NullArgumentException
 ifx
ory
arenull
.NoDataException
 ifx
ory
are zerolength.DimensionMismatchException
 ifx
andy
do not have the same length.

wilcoxonSignedRankTest
public double wilcoxonSignedRankTest(double[] x, double[] y, boolean exactPValue) throws NullArgumentException, NoDataException, DimensionMismatchException, NumberIsTooLargeException, ConvergenceException, MaxCountExceededException
Returns the observed significance level, or pvalue, associated with a Wilcoxon signed ranked statistic comparing mean for two related samples or repeated measurements on a single sample.Let X_{i} denote the i'th individual of the first sample and Y_{i} the related i'th individual in the second sample. Let Z_{i} = Y_{i}  X_{i}.
Preconditions:
 The differences Z_{i} must be independent.
 Each Z_{i} comes from a continuous population (they must be identical) and is symmetric about a common median.
 The values that X_{i} and Y_{i} represent are ordered, so the comparisons greater than, less than, and equal to are meaningful.
 Parameters:
x
 the first sampley
 the second sampleexactPValue
 if the exact pvalue is wanted (only works for x.length >= 30, if true and x.length < 30, this is ignored because calculations may take too long) Returns:
 pvalue
 Throws:
NullArgumentException
 ifx
ory
arenull
.NoDataException
 ifx
ory
are zerolength.DimensionMismatchException
 ifx
andy
do not have the same length.NumberIsTooLargeException
 ifexactPValue
istrue
andx.length
> 30ConvergenceException
 if the pvalue can not be computed due to a convergence errorMaxCountExceededException
 if the maximum number of iterations is exceeded

