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 }