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JSci is a set of open source Java packages. The aim is to encapsulate scientific methods/principles in the most natural way possible. As such they should greatly aid the development of scientific based software. It offers: abstract math interfaces, linear algebra (support for various matrix and vector types), statistics (including probability distributions), wavelets, newtonian mechanics, chart/graph components (AWT and Swing), MathML DOM implementation, ... Note: some packages, like javax.comm, for the astro and instruments package aren't listed as dependencies (not available).

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package JSci.maths.statistics;

/**
* The ParetoDistribution class provides an object for encapsulating Pareto distributions.
* @version 0.2
* @author Mark Hale
*/
public final class ParetoDistribution extends ProbabilityDistribution {
        private double shape;
        private double scale;

        /**
        * Constructs a Pareto distribution.
        * @param sh the shape.
        * @param sc the scale.
        */
        public ParetoDistribution(double sh,double sc) {
                if(sh<0.0)
                        throw new OutOfRangeException("The shape parameter should be positive.");
                shape=sh;
                if(sc<0.0)
                        throw new OutOfRangeException("The scale paremeter should be positive.");
                scale=sc;
        }
        /**
        * Returns the shape parameter.
        */
        public double getShapeParameter() {
                return shape;
        }
        /**
        * Returns the scale parameter.
        */
        public double getScaleParameter() {
                return scale;
        }
        /**
        * Returns the mean.
        */
        public double getMean() {
                return shape*scale/(shape-1.0);
        }
        /**
        * Returns the variance.
        */
        public double getVariance() {
                return shape*scale*scale/((shape-2.0)*(shape-1.0)*(shape-1.0));
        }
        /**
        * Probability density function of a Pareto distribution.
        * P(X) = (a/X) (s/X)^a.
        * @return the probability that a stochastic variable x has the value X, i.e. P(x=X).
        */
        public double probability(double X) {
                if(X