/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.math4.stat.inference;
import org.apache.commons.math4.exception.DimensionMismatchException;
import org.apache.commons.math4.exception.NoDataException;
import org.apache.commons.math4.exception.NullArgumentException;
import org.apache.commons.math4.exception.NumberIsTooLargeException;
import org.apache.commons.math4.stat.inference.WilcoxonSignedRankTest;
import org.junit.Assert;
import org.junit.Test;
/**
* Test cases for the WilcoxonSignedRangTest class.
*
*/
public class WilcoxonSignedRankTestTest {
protected WilcoxonSignedRankTest testStatistic = new WilcoxonSignedRankTest();
@Test
public void testWilcoxonSignedRankSimple() {
/* Target values computed using R version 2.11.1
* x <- c(1.83, 0.50, 1.62, 2.48, 1.68, 1.88, 1.55, 3.06, 1.30)
* y <- c(0.878, 0.647, 0.598, 2.05, 1.06, 1.29, 1.06, 3.14, 1.29)
*/
final double x[] = {1.83, 0.50, 1.62, 2.48, 1.68, 1.88, 1.55, 3.06, 1.30};
final double y[] = {0.878, 0.647, 0.598, 2.05, 1.06, 1.29, 1.06, 3.14, 1.29};
/* EXACT:
* wilcox.test(x, y, alternative = "two.sided", mu = 0, paired = TRUE, exact = TRUE, correct = FALSE)
* V = 40, p-value = 0.03906
*
* Corresponds to the value obtained in R.
*/
Assert.assertEquals(40, testStatistic.wilcoxonSignedRank(x, y), 1e-10);
Assert.assertEquals(0.03906, testStatistic.wilcoxonSignedRankTest(x, y, true), 1e-5);
/* ASYMPTOTIC:
* wilcox.test(x, y, alternative = "two.sided", mu = 0, paired = TRUE, exact = FALSE, correct = FALSE)
* V = 40, p-value = 0.03815
*
* This is not entirely the same due to different corrects,
* e.g. http://mlsc.lboro.ac.uk/resources/statistics/wsrt.pdf
* and src/library/stats/R/wilcox.test.R in the R source
*/
Assert.assertEquals(40, testStatistic.wilcoxonSignedRank(x, y), 1e-10);
Assert.assertEquals(0.0329693812, testStatistic.wilcoxonSignedRankTest(x, y, false), 1e-10);
}
@Test
public void testWilcoxonSignedRankInputValidation() {
/*
* Exact only for sample size <= 30
*/
final double[] x1 = new double[30];
final double[] x2 = new double[31];
final double[] y1 = new double[30];
final double[] y2 = new double[31];
for (int i = 0; i < 30; ++i) {
x1[i] = x2[i] = y1[i] = y2[i] = i;
}
// Exactly 30 is okay
//testStatistic.wilcoxonSignedRankTest(x1, y1, true);
try {
testStatistic.wilcoxonSignedRankTest(x2, y2, true);
Assert.fail("More than 30 samples and exact chosen, NumberIsTooLargeException expected");
} catch (NumberIsTooLargeException ex) {
// expected
}
/* Samples must be present, i.e. length > 0
*/
try {
testStatistic.wilcoxonSignedRankTest(new double[] { }, new double[] { 1.0 }, true);
Assert.fail("x does not contain samples (exact), NoDataException expected");
} catch (NoDataException ex) {
// expected
}
try {
testStatistic.wilcoxonSignedRankTest(new double[] { }, new double[] { 1.0 }, false);
Assert.fail("x does not contain samples (asymptotic), NoDataException expected");
} catch (NoDataException ex) {
// expected
}
try {
testStatistic.wilcoxonSignedRankTest(new double[] { 1.0 }, new double[] { }, true);
Assert.fail("y does not contain samples (exact), NoDataException expected");
} catch (NoDataException ex) {
// expected
}
try {
testStatistic.wilcoxonSignedRankTest(new double[] { 1.0 }, new double[] { }, false);
Assert.fail("y does not contain samples (asymptotic), NoDataException expected");
} catch (NoDataException ex) {
// expected
}
/* Samples not same size, i.e. cannot be pairred
*/
try {
testStatistic.wilcoxonSignedRankTest(new double[] { 1.0, 2.0 }, new double[] { 3.0 }, true);
Assert.fail("x and y not same size (exact), DimensionMismatchException expected");
} catch (DimensionMismatchException ex) {
// expected
}
try {
testStatistic.wilcoxonSignedRankTest(new double[] { 1.0, 2.0 }, new double[] { 3.0 }, false);
Assert.fail("x and y not same size (asymptotic), DimensionMismatchException expected");
} catch (DimensionMismatchException ex) {
// expected
}
/*
* x and y is null
*/
try {
testStatistic.wilcoxonSignedRankTest(null, null, true);
Assert.fail("x and y is null (exact), NullArgumentException expected");
} catch (NullArgumentException ex) {
// expected
}
try {
testStatistic.wilcoxonSignedRankTest(null, null, false);
Assert.fail("x and y is null (asymptotic), NullArgumentException expected");
} catch (NullArgumentException ex) {
// expected
}
/*
* x or y is null
*/
try {
testStatistic.wilcoxonSignedRankTest(null, new double[] { 1.0 }, true);
Assert.fail("x is null (exact), NullArgumentException expected");
} catch (NullArgumentException ex) {
// expected
}
try {
testStatistic.wilcoxonSignedRankTest(null, new double[] { 1.0 }, false);
Assert.fail("x is null (asymptotic), NullArgumentException expected");
} catch (NullArgumentException ex) {
// expected
}
try {
testStatistic.wilcoxonSignedRankTest(new double[] { 1.0 }, null, true);
Assert.fail("y is null (exact), NullArgumentException expected");
} catch (NullArgumentException ex) {
// expected
}
try {
testStatistic.wilcoxonSignedRankTest(new double[] { 1.0 }, null, false);
Assert.fail("y is null (asymptotic), NullArgumentException expected");
} catch (NullArgumentException ex) {
// expected
}
}
}