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: 670469 $ $Date: 2008-06-23 04:01:38 -0400 (Mon, 23 Jun 2008) $
023     */
024    public interface StatisticalSummary {
025        /** 
026         * Returns the <a href="http://www.xycoon.com/arithmetic_mean.htm">
027         * arithmetic mean </a> of the available values 
028         * @return The mean or Double.NaN if no values have been added.
029         */
030        public abstract double getMean();
031        /** 
032         * Returns the variance of the available values.
033         * @return The variance, Double.NaN if no values have been added 
034         * or 0.0 for a single value set.  
035         */
036        public abstract double getVariance();
037        /** 
038         * Returns the standard deviation of the available values.
039         * @return The standard deviation, Double.NaN if no values have been added 
040         * or 0.0 for a single value set. 
041         */
042        public abstract double getStandardDeviation();
043        /** 
044         * Returns the maximum of the available values
045         * @return The max or Double.NaN if no values have been added.
046         */
047        public abstract double getMax();
048        /** 
049        * Returns the minimum of the available values
050        * @return The min or Double.NaN if no values have been added.
051        */
052        public abstract double getMin();
053        /** 
054         * Returns the number of available values
055         * @return The number of available values
056         */
057        public abstract long getN();
058        /**
059         * Returns the sum of the values that have been added to Univariate.
060         * @return The sum or Double.NaN if no values have been added
061         */
062        public abstract double getSum();
063    }