using System.Collections.Generic;
using System.Linq;

namespace DTS.Utilities
{
    public class StandardDev
    {
        public static double StandardDeviation(IEnumerable<double> values)
        {
            double standardDeviation = 0;

            if (!values.Any()) return standardDeviation;
            // Compute the average.     
            double avg = values.Average();

            // Perform the Sum of (value-avg)_2_2.      
            double sum = values.Sum(d => System.Math.Pow(d - avg, 2));

            // Put it all together.      
            standardDeviation = System.Math.Sqrt((sum) / (values.Count() - 1));

            return standardDeviation;
        }
    }
}