standardDeviation.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace StandardDeviation
{
    public static class Program
    {
        static void Main(string[] args)
        {
            Random rnd = new Random();
            List<double> scores = new List<double>();
            
            for (int i = 0; i < 95; i++) 
            {
                scores.Add((double)rnd.Next(0, 100));
            }
            
            StandardDeviation(scores);
        }

        public static double StandardDeviation(this List<double> values)
        {
            double avg = values.Average();
            return Math.Sqrt(values.Average(v => Math.Pow(v - avg, 2)));
        } 
    }
}