计算标准差 Exercise07_11

import java.util.Scanner;
/**
 * @author 冰樱梦
 * 时间：2018年下半年
 * 题目：计算标准差
 *
 */
public class Exercise07_11 {
    public static void main(String[] args){
        Scanner input=new Scanner(System.in);
        double[] array=new double[10];
        System.out.println("Enter 10 numbers: ");
        for(int i=0;i<array.length;i++){
            array[i]=input.nextDouble();
        }
        System.out.printf("%s%.2f\n","The mean is: ",mean(array));
        System.out.printf("%s%.5f","The standard deviation is: ",deviation(array));
    }
    
    //返回数组的平均值
    public static double mean(double[] x){
        double total=0;
        for(int i=0;i<x.length;i++){
            total+=x[i];
        }
        return total/x.length;
    }
    
    //返回数组的标准差
    public static double deviation(double[] x){
        double total=0;
        for(int i=0;i<x.length;i++){
            total+=Math.pow((x[i]-mean(x)),2);
        }
        return Math.pow(total/(x.length-1), 0.5);
    }
}