C:/Documents and Settings/Stephen/Desktop/Biostatistics Library and Program/Biostatistics/RelativeRiskTest.cs

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using System;

namespace StephenAshley.Biostatistics
{
   using NUMBER = Decimal;

   public class RelativeRiskTest
   {
      public RelativeRiskTest() { data = new Fields(); }

      public RelativeRiskTest(Int32 a, Int32 b, Int32 c, Int32 d)
      {
         data = new Fields(a, b, c, d);
      }

      private Fields data;

      public Int32 A()
      {
         return data.A;
      }

      public void SetA(Int32 value)
      {
         data.A = value;
      }

      public Int32 B()
      {
         return data.B;
      }

      public void SetB(Int32 value)
      {
         data.B = value;
      }

      public Int32 C()
      {
         return data.C;
      }

      public void SetC(Int32 value)
      {
         data.C = value;
      }

      public Int32 D()
      {
         return data.D;
      }

      public void SetD(Int32 value)
      {
         data.D = value;
      }

      public NUMBER ChiSquared()
      {
         ChiSquaredArray chiSquaredArray = new ChiSquaredArray(2, 2);
         chiSquaredArray.Add(0, 0, A());
         chiSquaredArray.Add(1, 0, B());
         chiSquaredArray.Add(0, 1, C());
         chiSquaredArray.Add(1, 1, D());

         NUMBER decResult = chiSquaredArray.ChiSquared();
         return decResult;
      }

      public NUMBER ConfidenceLevelUpperLimit()
      {
         NUMBER decD;
         try
         {
            NUMBER decA = 1.959964394569397m * StandardErrorOfLogOfRelativeRisk();
            NUMBER decB = DecMath.Log(RelativeRisk());
            NUMBER decC = decB + decA;
            decD = DecMath.Exp(decC);
         }
         catch (Exception e)
         {
            throw new BiostatisticsException(e.Source + ": " + e.Message, e);
         }
         return decD;
      }

      public NUMBER ConfidenceLevelLowerLimit()
      {
         NUMBER decD;
         try
         {
            NUMBER decA = 1.959964394569397m * StandardErrorOfLogOfRelativeRisk();
            NUMBER decB = DecMath.Log(RelativeRisk());
            NUMBER decC = decB - decA;
            decD = DecMath.Exp(decC);
         }
         catch (Exception e)
         {
            throw new BiostatisticsException(e.Source + ": " + e.Message, e);
         }
         return decD;
      }

      public NUMBER LogRelativeRisk()
      {
         NUMBER decResult;
         try
         {
            decResult = DecMath.Log(RelativeRisk());
         }
         catch (Exception e)
         {
            throw new BiostatisticsException(e.Source + ": " + e.Message, e);
         }
         return decResult;
      }

      public NUMBER p()
      {
         return Convert.ToDecimal(Distributions.ProbabilityChiSq(
               (double)ChiSquared(), 1));
      }

      public NUMBER RelativeRisk()
      {
         NUMBER decResult;
         try
         {
            decResult = (Convert.ToDecimal(A()) / Convert.ToDecimal(A() + B()))
                              /
                   (Convert.ToDecimal(C()) / Convert.ToDecimal(C() + D()));
         }
         catch (Exception e)
         {
            throw new BiostatisticsException(e.Source + ": " + e.Message, e);
         }
         return decResult;
      }

      public NUMBER StandardErrorOfLogOfRelativeRisk()
      {
         NUMBER decStandardErrorOfLogOfRelativeRisk = 0.0m;
         try
         {
         NUMBER decA = (NUMBER)A() / (NUMBER)(A() + B());
         NUMBER decB = 1.0m - decA;
         NUMBER decC = decB / (NUMBER)A();

         NUMBER decD = (NUMBER)C() / (NUMBER)(C() + D());
         NUMBER decE = 1.0m - decD;
         NUMBER decF = decE / (NUMBER)C();

         NUMBER decG = decC + decF;
         decStandardErrorOfLogOfRelativeRisk = DecMath.Sqrt(decG);
         double StandardErrorOfRelativeRisk = 
            Math.Exp((double)decStandardErrorOfLogOfRelativeRisk);
         }
         catch (Exception e)
         {
            throw new BiostatisticsException(e.Source + ": " + e.Message, e);
         }
         return decStandardErrorOfLogOfRelativeRisk;
      }

      private struct Fields
      {
         public Fields(Int32 A, Int32 B, Int32 C, Int32 D)
         {
            if (A < 0)
               throw new BiostatisticsException(
                  "A value in Fields constructor of RelativeRisk Text less than 0.");

            if (B < 0)
               throw new BiostatisticsException(
                  "B value in Fields constructor of RelativeRisk Text less than 0.");

            if (C < 0)
               throw new BiostatisticsException(
                  "C value in Fields constructor of RelativeRisk Text less than 0.");

            if (D < 0)
               throw new BiostatisticsException(
                  "D value in Fields constructor of RelativeRisk Text less than 0.");

            iA = A;
            iB = B;
            iC = C;
            iD = D;
         }

         public Fields(Fields fields)
         {
            iA = fields.iA;
            iB = fields.iB;
            iC = fields.iC;
            iD = fields.iD;
         }

         public Int32 A
         {
            get
            {
               return iA;
            }
            set
            {
               if (value < 0)
                  throw new BiostatisticsException(
                     "A value in Fields constructor of RelativeRiskText less than 0.");
               iA = value;
            }
         }

         public Int32 C
         {
            get
            {
               return iB;
            }
            set
            {
               if (value < 0)
                  throw new BiostatisticsException(
                     "B value in Fields constructor of RelativeRiskText less than 0.");
               iB = value;
            }
         }

         public Int32 B
         {
            get
            {
               return iC;
            }
            set
            {
               if (value < 0)
                  throw new BiostatisticsException(
                     "C value in Fields constructor of RelativeRiskText less than 0.");
               iC = value;
            }
         }

         public Int32 D
         {
            get
            {
               return iD;
            }
            set
            {
               if (value < 0)
                  throw new BiostatisticsException(
                     "D value in Fields constructor of RelativeRiskText less than 0.");
               iD = value;
            }
         }

         private Int32 iA, iB, iC, iD;
      }
   }
}

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