求输入数组的方差和平均值

import java.util.Scanner;
public class Task02 {
    public static void main(String[] args) {
        Scanner input=new Scanner(System.in);
        System.out.println("请输入数组长度");
        int a=input.nextInt();
        int[] arr=new int[a];
        System.out.println("请输入数据");
        double sum = 0;
        for(int i=0;i< a;i++){
            int b=input.nextInt();
            arr[i]=b;
        }
        for (int k=0;k<a;k++){
            sum+=arr[k];
        }
        double avg=sum/ a;
        System.out.println("平均值是"+avg);
        double f=0;
        for (int j=0;j<a;j++){
            f+=Math.pow(arr[j]-avg,2);
        }
        double s=f/a;
        System.out.println("数组方差是:"+s);
    }
}