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);
     }
 }