using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        float[] data = new float[] {1,2,3,4,5,6,7,8,9};

​

        var m = data.Average();

        var s = CalculateStdDev(data);

​

        float CalculateStdDev(IEnumerable<float> values)

        {

           double ret = 0;

​

           if (values.Count() > 0)

           {

              double avg = values.Average();

              double sum = values.Sum(d => Math.Pow(d - avg, 2));

              ret = Math.Sqrt((sum) / values.Count()-1);

           }

           return (float)ret;

        }

        Console.WriteLine(m);

        Console.WriteLine(s);

    }

}