| 1 | package de.uka.ipd.sdq.statistics.estimation; |
| 2 | |
| 3 | /** |
| 4 | * Represents a confidence interval. Whether one confidence interval contains |
| 5 | * another can be checked by using the {@link #contains(ConfidenceInterval)} |
| 6 | * method. |
| 7 | * |
| 8 | * @author Philipp Merkle |
| 9 | * |
| 10 | */ |
| 11 | public class ConfidenceInterval { |
| 12 | |
| 13 | private double lowerBound; |
| 14 | |
| 15 | private double upperBound; |
| 16 | |
| 17 | private double mean; |
| 18 | |
| 19 | private double level; |
| 20 | |
| 21 | /** |
| 22 | * Constructs a confidence interval around the specified mean, having bounds |
| 23 | * lowerBound and upperBound. |
| 24 | * |
| 25 | * @param mean |
| 26 | * the center of the confidence interval |
| 27 | * @param lowerBound |
| 28 | * the confidence interval's lower bound |
| 29 | * @param upperBound |
| 30 | * the confidence interval's upper bound |
| 31 | * @param level |
| 32 | * the confidence level. Use values between 0 and 1. For instance |
| 33 | * use 0.95 to estimate the 95% confidence interval. |
| 34 | * @param noOfObservations |
| 35 | * the number of observations this confidence interval is constructed from |
| 36 | */ |
| 37 | public ConfidenceInterval(double mean, double lowerBound, double upperBound, double level) { |
| 38 | this.mean = mean; |
| 39 | this.lowerBound = lowerBound; |
| 40 | this.upperBound = upperBound; |
| 41 | this.level = level; |
| 42 | } |
| 43 | |
| 44 | /** |
| 45 | * Constructs a confidence interval around the specified mean having width |
| 46 | * (2 * mean * halfWidth). |
| 47 | * |
| 48 | * @param mean |
| 49 | * the center of the confidence interval |
| 50 | * @param halfWidth |
| 51 | * the relative half-width. Use values between 0 and 1. For |
| 52 | * instance use 0.1 in order to specify a 10% half-width. |
| 53 | */ |
| 54 | public ConfidenceInterval(double mean, double halfWidth, double level) { |
| 55 | this(mean, mean - mean * halfWidth, mean + mean * halfWidth, level); |
| 56 | } |
| 57 | |
| 58 | public double getLowerBound() { |
| 59 | return lowerBound; |
| 60 | } |
| 61 | |
| 62 | public void setLowerBound(double lowerBound) { |
| 63 | this.lowerBound = lowerBound; |
| 64 | } |
| 65 | |
| 66 | public double getUpperBound() { |
| 67 | return upperBound; |
| 68 | } |
| 69 | |
| 70 | public void setUpperBound(double upperBound) { |
| 71 | this.upperBound = upperBound; |
| 72 | } |
| 73 | |
| 74 | public double getMean() { |
| 75 | return mean; |
| 76 | } |
| 77 | |
| 78 | public void setMean(double mean) { |
| 79 | this.mean = mean; |
| 80 | } |
| 81 | |
| 82 | |
| 83 | public double getLevel() { |
| 84 | return level; |
| 85 | } |
| 86 | |
| 87 | /** |
| 88 | * Checks, whether the specified confidence interval lies within the bounds |
| 89 | * of this confidence interval. |
| 90 | * |
| 91 | * @param ci |
| 92 | * the confidence interval |
| 93 | * @return true if this confidence interval contains the specified one; |
| 94 | * false else. |
| 95 | */ |
| 96 | public boolean contains(ConfidenceInterval ci) { |
| 97 | return ci != null |
| 98 | && this.lowerBound <= ci.getLowerBound() |
| 99 | && this.upperBound >= ci.getUpperBound(); |
| 100 | } |
| 101 | |
| 102 | } |