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1   package baseCode.math.distribution;
2   
3   import cern.jet.stat.Probability;
4   
5   /***
6    * <hr>
7    * <p>
8    * Copyright (c) 2004 Columbia University
9    * 
10   * @author pavlidis
11   * @version $Id: NormalProbabilityComputer.java,v 1.1 2004/12/31 01:14:48 pavlidis Exp $
12   */
13  public class NormalProbabilityComputer implements ProbabilityComputer {
14  
15     double variance;
16     double mean;
17  
18     /***
19      * @param variance
20      * @param mean
21      */
22     public NormalProbabilityComputer( double variance, double mean ) {
23        super();
24        this.variance = variance;
25        
26        if (variance < 0) {
27           throw new IllegalArgumentException("Variance must be non-negative");
28        }
29  
30        this.mean = mean;
31     }
32  
33     /*
34      * (non-Javadoc)
35      * 
36      * @see baseCode.math.ProbabilityComputer#probability(double)
37      */
38     public double probability( double value ) {
39        return 1.0 - Probability.normal( mean, variance, value );
40     }
41  
42     public double probability( double value, boolean upperTail ) {
43        if ( upperTail ) {
44           return probability( value );
45        }
46  
47        return Probability.normal( mean, variance, value );
48  
49     }
50  
51  }