import java.io.*;
class estad1
{
	public static void main(String arg[]) throws IOException
	{
		BufferedReader in = new BufferedReader(new 
			InputStreamReader(System.in));
		int tam;
		
		System.out.println("\n Pograma de estadistica\n"); 
		System.out.print(" Ingrese el numero de datos : "); 
		tam = Integer.parseInt(in.readLine( ));  
		System.out.println( );
		
		if(tam > 1)
		{
			int arreglo[] = new int[tam];
         	
			/* Lectura del arreglo */

         	for(int i = 0; i < arreglo.length; i++)
         	{
         		System.out.print(" Ingrese elemento " + i + " : ");
         		arreglo[ i ] = Integer.parseInt(in.readLine()); 	
         	}
			
			System.out.println("\n Resultados \n");
			
			double aux_media = media(arreglo);
			System.out.println(" media : " + aux_media);
			
			double aux_var = varianza(arreglo,aux_media);
			System.out.println(" varianza : " + aux_var);
			System.out.println(" desv. estandar : " + Math.sqrt(aux_var));
		}
		else
		{
			System.out.println("\n numero de elementos no valido!");	
		}
	
		System.out.println();
	}

	public static double media(int arr[])
	{
		double sum = 0.0;

		for(int i = 0; i < arr.length ; i++)
		{
			sum += arr[i];
		}

		return sum / arr.length;
	}	
	
	public static double varianza(int arr[], double media)
	{
		double sum = 0.0;

		for(int i = 0; i < arr.length ; i++)
		{
			sum += Math.pow(arr[i] - media, 2);
		}
		
		return sum / (arr.length - 1);
	}

}