01: /*
02: * Copyright 2004 The Apache Software Foundation.
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
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: /**
32: * Returns the variance of the available values.
33: * @return The variance, Double.NaN if no values have been added
34: * or 0.0 for a single value set.
35: */
36: public abstract double getVariance();
37:
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: public abstract double getStandardDeviation();
44:
45: /**
46: * Returns the maximum of the available values
47: * @return The max or Double.NaN if no values have been added.
48: */
49: public abstract double getMax();
50:
51: /**
52: * Returns the minimum of the available values
53: * @return The min or Double.NaN if no values have been added.
54: */
55: public abstract double getMin();
56:
57: /**
58: * Returns the number of available values
59: * @return The number of available values
60: */
61: public abstract long getN();
62:
63: /**
64: * Returns the sum of the values that have been added to Univariate.
65: * @return The sum or Double.NaN if no values have been added
66: */
67: public abstract double getSum();
68: }
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