HW5.21

 import java.util.Scanner;

 public class Solution
 {
     public static void main(String[] args)
     {
         Scanner input = new Scanner(System.in);
         double[] array = new double[10];

         System.out.print("Enter 10 numbers: ");
         for(int i = 0; i < array.length; i++)
             array[i] = input.nextDouble();

         input.close();

         System.out.println("The mean is " + getAverage(array));
         System.out.println("The standard deviation is " + getStandardDeviation(array));
     }

     public static double getAverage(double[] array)
     {
         double sum = 0;
         for(int i = 0; i < array.length; i++)
             sum += array[i];
         double average = sum / array.length;
         return average;
     }

     public static double getStandardDeviation(double[] array)
     {
         double sum1 = 0;
         double sum2 = 0;
         for(int i = 0; i < array.length; i++)
         {
             sum1 += array[i] * array[i];
             sum2 += array[i];
         }
         double standardDeviation = Math.sqrt((sum1 - sum2 * sum2 / array.length) / (array.length - 1));
         return standardDeviation;
     }
 }