package com.imsl.test.example.stat;

import com.imsl.stat.*;

/**
 * <p>
 * Performs a difference in means test with incremental updates.
 * </p>
 * <p>
 * The same data is used for this example as for the example
 * {@link NormTwoSampleEx1}.</p>
 * <p>
 * This example demonstrates how the analysis can be applied to subsets of the
 * original data set using different update methods. These techniques may be
 * useful when analyzing data sets too large to fit into memory.</p>
 *
 * @see <a href="NormTwoSampleEx2.java">Code</a>
 * @see <a href="doc-files/NormTwoSampleEx2.out">Output</a>
 */
public class NormTwoSampleEx2 {

    public static void main(String args[]) {
        // Bring in first group of observations on x1 and x2.
        // 2 observations first and then 1 observation.
        double[] x1blk = {72.0, 75.0};
        double[] x2blk = {111.0, 118.0};
        NormTwoSample n2samp = new NormTwoSample(x1blk, x2blk);

        // Use different update methods.
        double[] x1blk1 = {77.0};
        double[] x2blk1 = {128.0};
        n2samp.updateX(x1blk1);
        n2samp.updateY(x2blk1);

        // Second group.
        double[] x1blk2 = {80.0, 104.0, 110.0, 125.0};
        double[] x2blk2 = {138.0, 140.0, 150.0, 163.0};
        n2samp.update(x1blk2, x2blk2);

        // Third group.
        double[] x2blk3 = {164.0, 169.0};
        n2samp.updateY(x2blk3);

        double mean = n2samp.getDiffMean();

        System.out.println("x1mean-x2mean  = " + mean);
        System.out.println("X1 mean = " + n2samp.getMeanX());
        System.out.println("X2 mean = " + n2samp.getMeanY());

        double pVar = n2samp.getPooledVariance();
        System.out.println("pooledVar = " + pVar);

        double loCI = n2samp.getLowerCIDiff();
        double upCI = n2samp.getUpperCIDiff();
        System.out.println("95% CI for the mean is "
                + loCI + " " + upCI);

        loCI = n2samp.getLowerCIDiff();
        upCI = n2samp.getUpperCIDiff();
        System.out.println("95% CI for the ueq mean is "
                + loCI + " " + upCI);

        System.out.println("T Test Results");
        double tDF = n2samp.getTTestDF();
        double tT = n2samp.getTTest();
        double tPval = n2samp.getTTestP();
        System.out.println("T default = " + tDF);
        System.out.println("t = " + tT);
        System.out.println("p-value = " + tPval);

        double stdevX = n2samp.getStdDevX();
        double stdevY = n2samp.getStdDevY();
        System.out.println("stdev x1 = " + stdevX);
        System.out.println("stdev x2 = " + stdevY);
    }
}