geogebra.common.kernel.statistics.AlgoZProportion2Estimate.java Source code

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Here is the source code for geogebra.common.kernel.statistics.AlgoZProportion2Estimate.java

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/* 
GeoGebra - Dynamic Mathematics for Everyone
http://www.geogebra.org
    
This file is part of GeoGebra.
    
This program is free software; you can redistribute it and/or modify it 
under the terms of the GNU General Public License as published by 
the Free Software Foundation.
    
 */

package geogebra.common.kernel.statistics;

import geogebra.common.kernel.Construction;
import geogebra.common.kernel.algos.AlgoElement;
import geogebra.common.kernel.commands.Commands;
import geogebra.common.kernel.geos.GeoElement;
import geogebra.common.kernel.geos.GeoList;
import geogebra.common.kernel.geos.GeoNumeric;

import org.apache.commons.math.distribution.NormalDistributionImpl;

/**
 * 
 * 
 * @author G. Sturr
 */
public class AlgoZProportion2Estimate extends AlgoElement {

    private GeoNumeric proportion, n, proportion2, n_2, level; // input
    private GeoList result; // output
    private double se;
    private double me;

    /**
     * @param cons
     * @param label
     * @param proportion
     * @param n
     * @param proportion2
     * @param n_2
     * @param level
     */
    public AlgoZProportion2Estimate(Construction cons, String label, GeoNumeric proportion, GeoNumeric n,
            GeoNumeric proportion2, GeoNumeric n_2, GeoNumeric level) {
        this(cons, proportion, n, proportion2, n_2, level);
        result.setLabel(label);
    }

    /**
     * @param cons
     * @param proportion
     * @param n
     * @param proportion2
     * @param n_2
     * @param level
     */
    public AlgoZProportion2Estimate(Construction cons, GeoNumeric proportion, GeoNumeric n, GeoNumeric proportion2,
            GeoNumeric n_2, GeoNumeric level) {
        super(cons);
        this.proportion = proportion;
        this.n = n;
        this.proportion2 = proportion2;
        this.n_2 = n_2;
        this.level = level;
        result = new GeoList(cons);
        setInputOutput(); // for AlgoElement

        compute();
    }

    @Override
    public Commands getClassName() {
        return Commands.ZProportion2Estimate;
    }

    @Override
    protected void setInputOutput() {

        input = new GeoElement[5];
        input[0] = proportion;
        input[1] = n;
        input[2] = proportion2;
        input[3] = n_2;
        input[4] = level;

        setOnlyOutput(result);
        setDependencies(); // done by AlgoElement
    }

    /**
     * @return {lower confidence limit, upper confidence limit}.
     */
    public GeoList getResult() {
        return result;
    }

    /**
     * @return margin of error
     */
    public double getME() {
        return me;
    }

    /**
     * @return standard error
     */
    public double getSE() {
        return se;
    }

    @Override
    public final void compute() {

        double n1 = n.getDouble();
        double phat1 = proportion.getDouble();
        double n2 = n_2.getDouble();
        double phat2 = proportion2.getDouble();
        double cLevel = level.getDouble();

        NormalDistributionImpl normalDist = new NormalDistributionImpl(0, 1);

        double critZ = 0;

        try {
            critZ = normalDist.inverseCumulativeProbability((1 - cLevel) / 2);
        } catch (Exception e) {
            result.setUndefined();
            return;
        }

        double stat = phat1 - phat2;
        se = Math.sqrt(phat1 * (1 - phat1) / n1 + phat2 * (1 - phat2) / n2);
        double z = Math.abs(critZ);
        me = z * se;

        // put these results into the output list
        result.clear();
        result.add(new GeoNumeric(cons, stat - me));
        result.add(new GeoNumeric(cons, stat + me));

    }

}