Mean, Median, Mode C#

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

namespace MeanMedianMode
{
    class Program
    {
        private static Random rng = new Random();

        private static int[] numberArray;
        private static double meanResult = 0;
        private static double medianResult = 0;
        private static double modeResult = 0;

        static void Main(string[] args)
        {
            numberArray = new int[10] { 64630, 11735, 11736, 99233, 14470, 4978, 73429, 38120, 51135, 67060 };

            Console.WriteLine($"Mean: {Mean(10).ToString("#.##")}");
            Console.WriteLine($"Median: {Median().ToString("#.##")}");
            Console.WriteLine($"Mode: {Mode()}");

            Console.ReadLine();
        }

        /*
        private static int[] CreateArray(int amountOfElements)
        {
            return numberArray = new int[amountOfElements];
        }

        private static void PopulateArray(int randomMaxValue)
        {
            for (int i = 0; i < numberArray.Length; i++)
            {
                numberArray[i] = rng.Next(10, randomMaxValue);
            }
        }
        */

        private static double Mean(int amountOfElements)
        {
            if (amountOfElements > numberArray.Length)
            {
                Console.WriteLine("Wrong amount of elements. Application will close.");
                Console.ReadLine();
                Environment.Exit(1);
            } else
            {
                for (int i = 0; i < amountOfElements; i++)
                {
                    meanResult += numberArray[i];
                }
            }
            meanResult = meanResult / amountOfElements;

            return meanResult;
        }

        private static double Median()
        {
            int[] numberArray_Sorted = numberArray.OrderByDescending(x => x).ToArray();

            if (numberArray_Sorted.Length % 2 == 0)
            {
                int n1 = (numberArray_Sorted.Length / 2) -1;
                int n2 = (numberArray_Sorted.Length / 2);
                medianResult = (double)(numberArray_Sorted[n1] + numberArray_Sorted[n2]) / 2;
            } else
            if (numberArray_Sorted.Length % 2 != 0)
            {
                int pos = (numberArray_Sorted.Length / 2);
                medianResult = numberArray_Sorted[pos];
            }

            return medianResult;
        }

        private static double Mode()
        {
            Array.Sort(numberArray);
            var groups = numberArray.GroupBy(x => x).OrderByDescending(o => o.Count()).Select(s => s.Key).FirstOrDefault();
            modeResult = groups;
            return modeResult;
        }
    }
}