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 */
017package org.apache.commons.math4.stat.descriptive;
018
019/**
020 *  Reporting interface for basic univariate statistics.
021 *
022 */
023public interface StatisticalSummary {
024
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    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    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    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    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    double getMin();
053    /**
054     * Returns the number of available values
055     * @return The number of available values
056     */
057    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    double getSum();
063
064}