Java List std varianceDouble(List list, boolean populationStandardDeviation)

Description

Variance double.

License

Apache License

Parameter

Parameter	Description
list	the list
populationStandardDeviation	the population standard deviation

Return

the double

Declaration

public static double varianceDouble(List<Double> list, boolean populationStandardDeviation) 

Method Source Code

//package com.java2s;
/*/*w ww  . ja v a  2 s .c o m*/
Copyright 2014 Array-Utilities
    
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
    
http://www.apache.org/licenses/LICENSE-2.0
    
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
    
 * */

import java.util.List;

public class Main {
    /**
     * Variance double.
     *
     * @param list the list
     * @param populationStandardDeviation the population standard deviation
     * @return the double
     */
    public static double varianceDouble(List<Double> list, boolean populationStandardDeviation) {

        double mean = meanDouble(list);
        double variance = 0;
        for (int i = 0; i < list.size(); i++) {
            double a = Math.pow(list.get(i) - mean, 2);
            variance += a;
        }
        if (populationStandardDeviation) {
            return variance / list.size();
        }
        return variance / (list.size() - 1);
    }

    /**
     * Mean double.
     *
     * @param list the list
     * @return the double
     */
    public static double meanDouble(List<Double> list) {

        return sumDouble(list) / list.size();
    }

    public static double sumDouble(List<Double> list) {

        double sum = 0;
        for (int i = 0; i < list.size(); i++) {
            sum += list.get(i);
        }
        return sum;
    }
}

Related

1. stdDev(List nums)
2. stddev(List observations)
3. stDev(final List list)
4. stdev(List values)
5. stdInt(List elements)