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Added chisquare test assertion. 

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@949536 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Phil Steitz 2010-05-30 17:03:27 +00:00
parent edd22d7ad5
commit 392b44b0a8
1 changed files with 76 additions and 0 deletions
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76
src/test/java/org/apache/commons/math/TestUtils.java
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@ -22,6 +22,7 @@ import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.text.DecimalFormat;
import junit.framework.Assert;
import junit.framework.AssertionFailedError;
@ -30,6 +31,8 @@ import org.apache.commons.math.complex.Complex;
import org.apache.commons.math.complex.ComplexFormat;
import org.apache.commons.math.linear.FieldMatrix;
import org.apache.commons.math.linear.RealMatrix;
import org.apache.commons.math.stat.inference.ChiSquareTest;
import org.apache.commons.math.stat.inference.ChiSquareTestImpl;
/**
* @version $Revision$ $Date$
@ -361,5 +364,78 @@ public class TestUtils {
}
return sumsq;
}
/**
* Asserts the null hypothesis for a ChiSquare test. Fails and dumps arguments and test
* statistics if the null hypothesis can be rejected with confidence 100 * (1 - alpha)%
*
* @param valueLabels
* @param expected expected counts
* @param observed observed counts
* @param alpha significance level of the test
*/
public static void assertChiSquareAccept(String[] valueLabels, double[] expected, long[] observed, double alpha) throws Exception {
ChiSquareTest chiSquareTest = new ChiSquareTestImpl();
try {
// Fail if we can reject null hypothesis that distributions are the same
Assert.assertFalse(chiSquareTest.chiSquareTest(expected, observed, alpha));
} catch (AssertionFailedError ex) {
StringBuffer msgBuffer = new StringBuffer();
DecimalFormat df = new DecimalFormat("#.##");
msgBuffer.append("Chisquare test failed");
msgBuffer.append(" p-value = ");
msgBuffer.append(chiSquareTest.chiSquareTest(expected, observed));
msgBuffer.append(" chisquare statistic = ");
msgBuffer.append(chiSquareTest.chiSquare(expected, observed));
msgBuffer.append(". \n");
msgBuffer.append("value\texpected\tobserved\n");
for (int i = 0; i < expected.length; i++) {
msgBuffer.append(valueLabels[i]);
msgBuffer.append("\t");
msgBuffer.append(df.format(expected[i]));
msgBuffer.append("\t\t");
msgBuffer.append(observed[i]);
msgBuffer.append("\n");
}
msgBuffer.append("This test can fail randomly due to sampling error with probability ");
msgBuffer.append(alpha);
msgBuffer.append(".");
Assert.fail(msgBuffer.toString());
}
}
/**
* Asserts the null hypothesis for a ChiSquare test. Fails and dumps arguments and test
* statistics if the null hypothesis can be rejected with confidence 100 * (1 - alpha)%
*
* @param values
* @param expected expected counts
* @param observed observed counts
* @param alpha significance level of the test
*/
public static void assertChiSquareAccept(int[] values, double[] expected, long[] observed, double alpha) throws Exception {
String[] labels = new String[values.length];
for (int i = 0; i < values.length; i++) {
labels[i] = Integer.toString(values[i]);
}
assertChiSquareAccept(labels, expected, observed, alpha);
}
/**
* Asserts the null hypothesis for a ChiSquare test. Fails and dumps arguments and test
* statistics if the null hypothesis can be rejected with confidence 100 * (1 - alpha)%
*
* @param values
* @param expected expected counts
* @param observed observed counts
* @param alpha significance level of the test
*/
public static void assertChiSquareAccept(double[] values, double[] expected, long[] observed, double alpha) throws Exception {
String[] labels = new String[values.length];
for (int i = 0; i < values.length; i++) {
labels[i] = Double.toString(values[i]);
}
assertChiSquareAccept(labels, expected, observed, alpha);
}
}