import sk.uniba.fmph.pocprak.ioutils.*;
public class SimpleProgram {
  static double[] height= new double[5000];
  static int nevent = 0;
  static void ReadData() throws Exception{
    double[] data;
    InTextFile in = InTextFile.open("obezita.txt");
    while (true){
      data = in.readlnDoubles();
      if(data==null) break;
      if(data.length==2){
        height[nevent]=data[0];
        nevent++;
      }
    }
    in.close();
  }
  public static void main(String[] args) throws Exception{
    ReadData();
    double sum = 0.;
    double sum2 = 0.;
    for(int i=0;i<nevent;i++){
      double h = height[i];
      sum = sum + h;
      sum2 = sum2 + h*h;
    }
    double mean = sum/nevent;
    double sigma = Math.sqrt(sum2/nevent-mean*mean);
    OutTextFile STDOUT = OutTextFile.open();
    STDOUT.println("Stredna hodnota = "+mean+"    sigma = "+sigma);
  }
}