/* * 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. *
This interface handles only known distributions. If the distribution is * unknown and should be provided by a sample, then the {@link UnknownDistributionChiSquareTest * UnknownDistributionChiSquareTest} extended interface should be used instead.
* @version $Revision: 811685 $ $Date: 2009-09-05 19:36:48 +0200 (sam. 05 sept. 2009) $ */ public interface ChiSquareTest { /** * Computes the * Chi-Square statistic comparingobserved
and expected
* frequency counts.
* * This statistic can be used to perform a Chi-Square test evaluating the null hypothesis that * the observed counts follow the expected distribution.
** Preconditions:
* If any of the preconditions are not met, an
* IllegalArgumentException
is thrown.
observed
* frequency counts to those in the expected
array.
* * The number returned is the smallest significance level at which one can reject * the null hypothesis that the observed counts conform to the frequency distribution * described by the expected counts.
** Preconditions:
* If any of the preconditions are not met, an
* IllegalArgumentException
is thrown.
alpha
. Returns true iff the null hypothesis can be rejected
* with 100 * (1 - alpha) percent confidence.
*
* Example:
* To test the hypothesis that observed
follows
* expected
at the 99% level, use
* chiSquareTest(expected, observed, 0.01)
* Preconditions:
0 < alpha < 0.5
*
* If any of the preconditions are not met, an
* IllegalArgumentException
is thrown.
counts
* array, viewed as a two-way table.
*
* The rows of the 2-way table are
* count[0], ... , count[count.length - 1]
* Preconditions:
counts
must have at
* least 2 columns and at least 2 rows.
*
* If any of the preconditions are not met, an
* IllegalArgumentException
is thrown.
counts
* array, viewed as a two-way table.
*
* The rows of the 2-way table are
* count[0], ... , count[count.length - 1]
* Preconditions:
counts
must have at least 2 columns and
* at least 2 rows.
*
* If any of the preconditions are not met, an
* IllegalArgumentException
is thrown.
alpha
. Returns true iff the null hypothesis can be rejected
* with 100 * (1 - alpha) percent confidence.
*
* The rows of the 2-way table are
* count[0], ... , count[count.length - 1]
* Example:
* To test the null hypothesis that the counts in
* count[0], ... , count[count.length - 1]
* all correspond to the same underlying probability distribution at the 99% level, use
* chiSquareTest(counts, 0.01)
* Preconditions:
counts
must have at least 2 columns and
* at least 2 rows.
*
* If any of the preconditions are not met, an
* IllegalArgumentException
is thrown.