examples.stats.example1.Example1 Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of jstat Show documentation

Java Library for Statistical Analysis.

The newest version!

package examples.stats.example1;
import datasets.VectorDouble;
import datastructs.IVector;
import org.apache.commons.math3.stat.StatUtils;
import stats.utils.Resample;
import org.apache.commons.math3.distribution.NormalDistribution;

/**
 *
 * Category: Statistics
 * ID: MeanBootstrap
 * Illustration of basic bootstrap method for the mean
 * see also: https://machinelearningmastery.com/a-gentle-introduction-to-the-bootstrap-method/
 */


public class Example1 {


    public static void main(String[] args){


        // the size of the sample
        final int SIZE = 100;
        final int RESAMPLE_SIZE = 20;

        // how many bootstrap iterations to perform
        final int BOOST_ITRS = 100;

        // parameters for normal distribution
        final double MU = 0.8;
        final double SD = 0.1;

        // create a sample
        VectorDouble sample = new VectorDouble(SIZE);

        // normal distribution:
        // see https://commons.apache.org/proper/commons-math/javadocs/api-3.5/org/apache/commons/math3/distribution/NormalDistribution.html
        NormalDistribution dist = new NormalDistribution(MU, SD);

        for(int i=0; i resample = Resample.resample(sample, RESAMPLE_SIZE, 3);
            means[itr] = ((VectorDouble)resample).getMean();
        }

        // compute the mean of means
        double mean = StatUtils.mean(means);
        System.out.println("Mean of means: "+mean);

    }

}