import java.util.Scanner;
public class StdDev {
  public static void main(String[] args) {
    Scanner getInput = new Scanner(System.in);
    System.out.println("I calculate the mean and standard deviation");
    System.out.println("How many numbers do you have?");
    final int n = getInput.nextInt();
    System.out.printf("Enter the %d numbers\n", n);
    double[] x = new double[n];
    double sum=0;
    for (int i=0; i<n; i++) {
      x[i] = getInput.nextDouble();
      sum += x[i];
    }
    double mean = sum / n;
    double diffSquared=0;	// std dev is sqrt(diffSquared/n)
    for (int i=0; i<n; i++) {
      diffSquared += Math.pow(mean-x[i],2);
    }
    System.out.printf("The mean is %f and the standard deviation is %f\n",
		      mean, Math.sqrt(diffSquared/n));
  }
}
//Local Variables:
//c-basic-offset: 2
//compile-command: "javac StdDev.java"
//End: