Source Code : Variance: the square of the standard deviation.

Java Is Open Source Programming Language You Can Download From Java and Java Libraries From http://www.oracle.com. Click Here to download
We provide this code related to title for you to solve your developing problem easily. Libraries which is import in this program you can download from http://www.oracle.com. Click Here or search from google with Libraries Name you get jar file related it

Variance: the square of the standard deviation.

        
import java.util.Arrays;


/**
 * <p>Static methods for doing useful math</p><hr>
 *
 * @author  : $Author: brian $
 * @version : $Revision: 1.1 $
 *
 * <hr><p><font size="-1" color="#336699"><a href="http://www.mbari.org">
 * The Monterey Bay Aquarium Research Institute (MBARI)</a> provides this
 * documentation and code &quot;as is&quot;, with no warranty, express or
 * implied, of its quality or consistency. It is provided without support and
 * without obligation on the part of MBARI to assist in its use, correction,
 * modification, or enhancement. This information should not be published or
 * distributed to third parties without specific written permission from
 * MBARI.</font></p><br>
 *
 * <font size="-1" color="#336699">Copyright 2002 MBARI.<br>
 * MBARI Proprietary Information. All rights reserved.</font><br><hr><br>
 *
 */

public class Util{
    /**
     * Variance: the square of the standard deviation. A measure of the degree
     * of spread among a set of values; a measure of the tendency of individual
     * values to vary from the mean value.
     *
     * @param values
     * @return
     */
    public static double variance(double[] values) {
        double std = standardDeviation(values);
        return std * std;
    }
    /**
     * Standard deviation is a statistical measure of spread or variability.The
     * standard deviation is the root mean square (RMS) deviation of the values
     * from their arithmetic mean.
     *
     * <b>standardDeviation</b> normalizes values by (N-1), where N is the sample size.  This is the
     * sqrt of an unbiased estimator of the variance of the population from
     * which X is drawn, as long as X consists of independent, identically
     * distributed samples.
     *
     * @param values
     * @return
     */
    public static strictfp double standardDeviation(double[] values) {
        double mean = mean(values);
        double dv = 0D;
        for (double d : values) {
            double dm = d - mean;
            dv += dm * dm;
        }
        return Math.sqrt(dv / (values.length - 1));
//        double[] deviation = deviationFromMean(values);
//        double s = 0D;
//        for (double d : deviation) {
//            s += (d * d);
//        }
//        return Math.sqrt(s / values.length - 1);
    }

    /**
     * Calculate the mean of an array of values
     *
     * @param values The values to calculate
     * @return The mean of the values
     */
    public static strictfp double mean(double[] values) {
        return sum(values) / values.length;
    }
    /**
     * Sum up all the values in an array
     *
     * @param values an array of values
     * @return The sum of all values in the Array
     */
    public static strictfp double sum(double[] values) {
        if (values == null || values.length == 0) {
            throw new IllegalArgumentException("The data array either is null or does not contain any data.");
        }
        else {
            double sum = 0;
            for (int i = 0; i < values.length; i++) {
                sum += values[i];
            }
            return sum;
        }
    }
}

   
    
    
    
    
    
    
    
  

Thank with us