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      1 /*
      2  * Licensed to the Apache Software Foundation (ASF) under one or more
      3  * contributor license agreements.  See the NOTICE file distributed with
      4  * this work for additional information regarding copyright ownership.
      5  * The ASF licenses this file to You under the Apache License, Version 2.0
      6  * (the "License"); you may not use this file except in compliance with
      7  * the License.  You may obtain a copy of the License at
      8  *
      9  *      http://www.apache.org/licenses/LICENSE-2.0
     10  *
     11  * Unless required by applicable law or agreed to in writing, software
     12  * distributed under the License is distributed on an "AS IS" BASIS,
     13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14  * See the License for the specific language governing permissions and
     15  * limitations under the License.
     16  */
     17 package org.apache.commons.math.stat.descriptive;
     18 
     19 /**
     20  *  Reporting interface for basic univariate statistics.
     21  *
     22   * @version $Revision: 811786 $ $Date: 2009-09-06 11:36:08 +0200 (dim. 06 sept. 2009) $
     23  */
     24 public interface StatisticalSummary {
     25 
     26     /**
     27      * Returns the <a href="http://www.xycoon.com/arithmetic_mean.htm">
     28      * arithmetic mean </a> of the available values
     29      * @return The mean or Double.NaN if no values have been added.
     30      */
     31     double getMean();
     32     /**
     33      * Returns the variance of the available values.
     34      * @return The variance, Double.NaN if no values have been added
     35      * or 0.0 for a single value set.
     36      */
     37     double getVariance();
     38     /**
     39      * Returns the standard deviation of the available values.
     40      * @return The standard deviation, Double.NaN if no values have been added
     41      * or 0.0 for a single value set.
     42      */
     43     double getStandardDeviation();
     44     /**
     45      * Returns the maximum of the available values
     46      * @return The max or Double.NaN if no values have been added.
     47      */
     48     double getMax();
     49     /**
     50     * Returns the minimum of the available values
     51     * @return The min or Double.NaN if no values have been added.
     52     */
     53     double getMin();
     54     /**
     55      * Returns the number of available values
     56      * @return The number of available values
     57      */
     58     long getN();
     59     /**
     60      * Returns the sum of the values that have been added to Univariate.
     61      * @return The sum or Double.NaN if no values have been added
     62      */
     63     double getSum();
     64 
     65 }
     66