import java.util.ArrayList;

public class Variance {
    // Copy here sum from exercise 63
    public static int sum(ArrayList<Integer> list) {

        int sum = 0;

        for ( int a: list)
        {
            sum += a;
        }

        return sum;
    }

    // Copy here average from exercise 64
    public static double average(ArrayList<Integer> list) {

        double average = (1.0 * sum(list))/(list.size());

        return average;
    }

    public static double variance(ArrayList<Integer> list) {

        double variance = 0;

        for (double a : list) {
        variance = a - average(list);
        Math.pow(variance, 2);

        }// write code here
        return variance;
    }

    public static void main(String[] args) {
        ArrayList<Integer> list = new ArrayList<Integer>();
        list.add(3);
        list.add(2);
        list.add(7);
        list.add(2);

        System.out.println("The variance is: " + variance(list));
    }

}