private void btn_GenNum_Click(object sender, EventArgs e)
        {
            try
            {
                StatAPI.StatAPI statAPI = new StatAPI.StatAPI();
                statAPI.clearList();
                int n = 0;
                n = int.Parse(textBox_Num.Text);

                if (statAPI.checkValidN(n))
                {
                    statAPI.AddNRandomNumbers(n, 0, 50);
                    lbl_Numbers.Text = statAPI.PrintNumbers();

                    MessageBox.Show(String.Format("Standard Deviation: {0:N3}", statAPI.StandardDeviation(n)));
                }
                else
                {
                    MessageBox.Show("The entered value is invalid. Please enter a value between 5 and 20.");
                }
            }
            catch (FormatException f)
            {
                MessageBox.Show("Please enter a integer" + f);
                textBox_Num.Clear();
                textBox_Num.Focus();
            }
        }