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    1   /*
    2    * Copyright 2004 The Apache Software Foundation.
    3    *
    4    * Licensed under the Apache License, Version 2.0 (the "License");
    5    * you may not use this file except in compliance with the License.
    6    * You may obtain a copy of the License at
    7    *
    8    *      http://www.apache.org/licenses/LICENSE-2.0
    9    *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  package org.apache.commons.math.stat.descriptive;
    17
    18  /***
    19   *  Reporting interface for basic univariate statistics.
    20   *
    21    * @version $Revision: 155427 $ $Date: 2005-02-26 06:11:52 -0700 (Sat, 26 Feb 2005) $
    22   */
    23  public interface StatisticalSummary {
    24      /***
    25       * Returns the <a href="http://www.xycoon.com/arithmetic_mean.htm">
    26       * arithmetic mean </a> of the available values
    27       * @return The mean or Double.NaN if no values have been added.
    28       */
    29      public abstract double getMean();
    30      /***
    31       * Returns the variance of the available values.
    32       * @return The variance, Double.NaN if no values have been added
    33       * or 0.0 for a single value set.
    34       */
    35      public abstract double getVariance();
    36      /***
    37       * Returns the standard deviation of the available values.
    38       * @return The standard deviation, Double.NaN if no values have been added
    39       * or 0.0 for a single value set.
    40       */
    41      public abstract double getStandardDeviation();
    42      /***
    43       * Returns the maximum of the available values
    44       * @return The max or Double.NaN if no values have been added.
    45       */
    46      public abstract double getMax();
    47      /***
    48      * Returns the minimum of the available values
    49      * @return The min or Double.NaN if no values have been added.
    50      */
    51      public abstract double getMin();
    52      /***
    53       * Returns the number of available values
    54       * @return The number of available values
    55       */
    56      public abstract long getN();
    57      /***
    58       * Returns the sum of the values that have been added to Univariate.
    59       * @return The sum or Double.NaN if no values have been added
    60       */
    61      public abstract double getSum();
    62  }