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authorRaymond <siuchow@google.com>2015-04-02 10:43:13 -0700
committerRaymond <siuchow@google.com>2015-04-02 10:43:13 -0700
commitdee0849a9704d532af0b550146cbafbaa6ee1d19 (patch)
tree8ccce3a046c214fb609977b7fc53c40cef7f9ea5 /src/main/java/org/apache/commons/math/stat/inference/UnknownDistributionChiSquareTest.java
parent55b0a5efc929efa9615babd3e760547f94e3518e (diff)
downloadapache-commons-math-dee0849a9704d532af0b550146cbafbaa6ee1d19.tar.gz
third party library: apache-commons-mathandroid-cts-6.0_r9android-cts-6.0_r8android-cts-6.0_r7android-cts-6.0_r6android-cts-6.0_r5android-cts-6.0_r4android-cts-6.0_r32android-cts-6.0_r31android-cts-6.0_r30android-cts-6.0_r3android-cts-6.0_r29android-cts-6.0_r28android-cts-6.0_r27android-cts-6.0_r26android-cts-6.0_r25android-cts-6.0_r24android-cts-6.0_r23android-cts-6.0_r22android-cts-6.0_r21android-cts-6.0_r20android-cts-6.0_r2android-cts-6.0_r19android-cts-6.0_r18android-cts-6.0_r17android-cts-6.0_r16android-cts-6.0_r15android-cts-6.0_r14android-cts-6.0_r13android-cts-6.0_r12android-cts-6.0_r1android-6.0.1_r9android-6.0.1_r81android-6.0.1_r80android-6.0.1_r8android-6.0.1_r79android-6.0.1_r78android-6.0.1_r77android-6.0.1_r74android-6.0.1_r73android-6.0.1_r72android-6.0.1_r70android-6.0.1_r7android-6.0.1_r69android-6.0.1_r68android-6.0.1_r67android-6.0.1_r66android-6.0.1_r65android-6.0.1_r63android-6.0.1_r62android-6.0.1_r61android-6.0.1_r60android-6.0.1_r59android-6.0.1_r58android-6.0.1_r57android-6.0.1_r56android-6.0.1_r55android-6.0.1_r54android-6.0.1_r53android-6.0.1_r52android-6.0.1_r51android-6.0.1_r50android-6.0.1_r5android-6.0.1_r49android-6.0.1_r48android-6.0.1_r47android-6.0.1_r46android-6.0.1_r45android-6.0.1_r43android-6.0.1_r42android-6.0.1_r41android-6.0.1_r40android-6.0.1_r4android-6.0.1_r33android-6.0.1_r32android-6.0.1_r31android-6.0.1_r30android-6.0.1_r3android-6.0.1_r28android-6.0.1_r27android-6.0.1_r26android-6.0.1_r25android-6.0.1_r24android-6.0.1_r22android-6.0.1_r21android-6.0.1_r20android-6.0.1_r18android-6.0.1_r17android-6.0.1_r16android-6.0.1_r13android-6.0.1_r12android-6.0.1_r11android-6.0.1_r10android-6.0.1_r1android-6.0.0_r7android-6.0.0_r6android-6.0.0_r5android-6.0.0_r41android-6.0.0_r4android-6.0.0_r3android-6.0.0_r26android-6.0.0_r25android-6.0.0_r24android-6.0.0_r23android-6.0.0_r2android-6.0.0_r13android-6.0.0_r12android-6.0.0_r11android-6.0.0_r1marshmallow-releasemarshmallow-mr3-releasemarshmallow-mr2-releasemarshmallow-mr1-releasemarshmallow-mr1-devmarshmallow-dr1.6-releasemarshmallow-dr1.5-releasemarshmallow-dr1.5-devmarshmallow-dr-releasemarshmallow-dr-dragon-releasemarshmallow-dr-devmarshmallow-devmarshmallow-cts-release
Change-Id: I52a325624a7f0dd652b362a9840626d6d9f3c42b
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+/*
+ * 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.math.stat.inference;
+
+import org.apache.commons.math.MathException;
+
+/**
+ * An interface for Chi-Square tests for unknown distributions.
+ * <p>Two samples tests are used when the distribution is unknown <i>a priori</i>
+ * but provided by one sample. We compare the second sample against the first.</p>
+ *
+ * @version $Revision: 811685 $ $Date: 2009-09-05 19:36:48 +0200 (sam. 05 sept. 2009) $
+ * @since 1.2
+ */
+public interface UnknownDistributionChiSquareTest extends ChiSquareTest {
+
+ /**
+ * <p>Computes a
+ * <a href="http://www.itl.nist.gov/div898/software/dataplot/refman1/auxillar/chi2samp.htm">
+ * Chi-Square two sample test statistic</a> comparing bin frequency counts
+ * in <code>observed1</code> and <code>observed2</code>. The
+ * sums of frequency counts in the two samples are not required to be the
+ * same. The formula used to compute the test statistic is</p>
+ * <code>
+ * &sum;[(K * observed1[i] - observed2[i]/K)<sup>2</sup> / (observed1[i] + observed2[i])]
+ * </code> where
+ * <br/><code>K = &sqrt;[&sum(observed2 / &sum;(observed1)]</code>
+ * </p>
+ * <p>This statistic can be used to perform a Chi-Square test evaluating the null hypothesis that
+ * both observed counts follow the same distribution.</p>
+ * <p>
+ * <strong>Preconditions</strong>: <ul>
+ * <li>Observed counts must be non-negative.
+ * </li>
+ * <li>Observed counts for a specific bin must not both be zero.
+ * </li>
+ * <li>Observed counts for a specific sample must not all be 0.
+ * </li>
+ * <li>The arrays <code>observed1</code> and <code>observed2</code> must have the same length and
+ * their common length must be at least 2.
+ * </li></ul></p><p>
+ * If any of the preconditions are not met, an
+ * <code>IllegalArgumentException</code> is thrown.</p>
+ *
+ * @param observed1 array of observed frequency counts of the first data set
+ * @param observed2 array of observed frequency counts of the second data set
+ * @return chiSquare statistic
+ * @throws IllegalArgumentException if preconditions are not met
+ */
+ double chiSquareDataSetsComparison(long[] observed1, long[] observed2)
+ throws IllegalArgumentException;
+
+ /**
+ * <p>Returns the <i>observed significance level</i>, or <a href=
+ * "http://www.cas.lancs.ac.uk/glossary_v1.1/hyptest.html#pvalue">
+ * p-value</a>, associated with a Chi-Square two sample test comparing
+ * bin frequency counts in <code>observed1</code> and
+ * <code>observed2</code>.
+ * </p>
+ * <p>The number returned is the smallest significance level at which one
+ * can reject the null hypothesis that the observed counts conform to the
+ * same distribution.
+ * </p>
+ * <p>See {@link #chiSquareDataSetsComparison(long[], long[])} for details
+ * on the formula used to compute the test statistic. The degrees of
+ * of freedom used to perform the test is one less than the common length
+ * of the input observed count arrays.
+ * </p>
+ * <strong>Preconditions</strong>: <ul>
+ * <li>Observed counts must be non-negative.
+ * </li>
+ * <li>Observed counts for a specific bin must not both be zero.
+ * </li>
+ * <li>Observed counts for a specific sample must not all be 0.
+ * </li>
+ * <li>The arrays <code>observed1</code> and <code>observed2</code> must
+ * have the same length and
+ * their common length must be at least 2.
+ * </li></ul><p>
+ * If any of the preconditions are not met, an
+ * <code>IllegalArgumentException</code> is thrown.</p>
+ *
+ * @param observed1 array of observed frequency counts of the first data set
+ * @param observed2 array of observed frequency counts of the second data set
+ * @return p-value
+ * @throws IllegalArgumentException if preconditions are not met
+ * @throws MathException if an error occurs computing the p-value
+ */
+ double chiSquareTestDataSetsComparison(long[] observed1, long[] observed2)
+ throws IllegalArgumentException, MathException;
+
+ /**
+ * <p>Performs a Chi-Square two sample test comparing two binned data
+ * sets. The test evaluates the null hypothesis that the two lists of
+ * observed counts conform to the same frequency distribution, with
+ * significance level <code>alpha</code>. Returns true iff the null
+ * hypothesis can be rejected with 100 * (1 - alpha) percent confidence.
+ * </p>
+ * <p>See {@link #chiSquareDataSetsComparison(long[], long[])} for
+ * details on the formula used to compute the Chisquare statistic used
+ * in the test. The degrees of of freedom used to perform the test is
+ * one less than the common length of the input observed count arrays.
+ * </p>
+ * <strong>Preconditions</strong>: <ul>
+ * <li>Observed counts must be non-negative.
+ * </li>
+ * <li>Observed counts for a specific bin must not both be zero.
+ * </li>
+ * <li>Observed counts for a specific sample must not all be 0.
+ * </li>
+ * <li>The arrays <code>observed1</code> and <code>observed2</code> must
+ * have the same length and their common length must be at least 2.
+ * </li>
+ * <li> <code> 0 < alpha < 0.5 </code>
+ * </li></ul><p>
+ * If any of the preconditions are not met, an
+ * <code>IllegalArgumentException</code> is thrown.</p>
+ *
+ * @param observed1 array of observed frequency counts of the first data set
+ * @param observed2 array of observed frequency counts of the second data set
+ * @param alpha significance level of the test
+ * @return true iff null hypothesis can be rejected with confidence
+ * 1 - alpha
+ * @throws IllegalArgumentException if preconditions are not met
+ * @throws MathException if an error occurs performing the test
+ */
+ boolean chiSquareTestDataSetsComparison(long[] observed1, long[] observed2, double alpha)
+ throws IllegalArgumentException, MathException;
+
+}