001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.math.stat.descriptive;
018    
019    /**
020     *  Reporting interface for basic univariate statistics.
021     *
022      * @version $Revision: 811786 $ $Date: 2009-09-06 11:36:08 +0200 (dim. 06 sept. 2009) $
023     */
024    public interface StatisticalSummary {
025    
026        /**
027         * Returns the <a href="http://www.xycoon.com/arithmetic_mean.htm">
028         * arithmetic mean </a> of the available values
029         * @return The mean or Double.NaN if no values have been added.
030         */
031        double getMean();
032        /**
033         * Returns the variance of the available values.
034         * @return The variance, Double.NaN if no values have been added
035         * or 0.0 for a single value set.
036         */
037        double getVariance();
038        /**
039         * Returns the standard deviation of the available values.
040         * @return The standard deviation, Double.NaN if no values have been added
041         * or 0.0 for a single value set.
042         */
043        double getStandardDeviation();
044        /**
045         * Returns the maximum of the available values
046         * @return The max or Double.NaN if no values have been added.
047         */
048        double getMax();
049        /**
050        * Returns the minimum of the available values
051        * @return The min or Double.NaN if no values have been added.
052        */
053        double getMin();
054        /**
055         * Returns the number of available values
056         * @return The number of available values
057         */
058        long getN();
059        /**
060         * Returns the sum of the values that have been added to Univariate.
061         * @return The sum or Double.NaN if no values have been added
062         */
063        double getSum();
064    
065    }