Process Performance Determination in C#

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

namespace ProcessPreformance
{
    /// <summary>
    /// Normal probabilities Result class
    /// </summary>
    public class NormalResult
    {
        /// <summary>
        /// Default constructor
        /// </summary>
        public NormalResult() { }
        /// <summary>
        /// cdf
        /// </summary>
        public double cdf;        
    }

    /// <summary>
    /// Determine Normal probabilities
    /// </summary>
    public class Normal
    {
        private double a1 = 0.254829592;
        private double a2 = -0.284496736;
        private double a3 = 1.421413741;
        private double a4 = -1.453152027;
        private double a5 = 1.061405429;
        private double p = 0.3275911;

        /// <summary>
        /// Normal Result
        /// </summary>
        public NormalResult Result = new NormalResult();

        #region Constructors
        /// <summary>
        /// Process performace  from DPMO constructor
        /// </summary>
        public Normal() { } //default empty constructor

        #endregion //Constructors

    }
}