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 }