计算公式：

并通过以下代码对Mahout in Action的结果进行了验证：

代码例如以下：

`

package com.example.mahout;

public class TestColl {

public static void main(String[] args) {    // TODO Auto-generated method stub    //int a[]={68,71,62,75,58,60,67,68,71,69,68,67,63,62,60,63,65,67,63,61};    //double b[] ={4.1,4.6,3.8,4.4,3.2,3.1,3.8,4.1,4.3,3.7,3.5,3.2,3.7,3.3,3.4,4.0,4.1,3.8,3.4,3.6};    double a[]={5,3.0,2.5};    double b[]={4,3,2.0};    int i,j;    double sum_a=0,sum_b=0,sum_XY=0,sum_X=0,sum_Y=0,sum_X2=0,sum_Y2=0;    double  mean_a,var_a,mean_b,var_b;    for(i=0;i

}

`