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 }