Problem 7.11 Computing Deviation

/*
 * Lu Liu
 * 11/19/2015
 * CSCI-111-D01
 * Problem 7.11 on page 278
 * Computing Deviation
 */
package chapter07;

import java.util.Scanner;

public class ComputingDeviation {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        double[] numbers = new double[200];
        System.out.println("Enter your numbers: ");
        for (int i = 0; i < numbers.length; i++) {
            numbers[i] = input.nextDouble();
        }
        displayArray(numbers);
        System.out.println("The mean is " + mean(numbers));
        System.out.println("The deviation is " + deviation(numbers));
    }

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

    public static double deviation(double[] x) {
        double mean = mean(x);
        double sum = 0;
        for (int i = 0; i < x.length; i++)
            sum += (x[i] - mean) * (x[i] - mean);
        return Math.sqrt(sum / (x.length - 1));
    }

    public static void displayArray(double[] x) {
        for (int i = 0; i < x.length; i++) {
            if ((i + 1) % 20 == 0)
                System.out.println(x[i]);
            else
                System.out.print(x[i] + " ");
        }
    }
}