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 }