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

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

namespace StephenAshley.Biostatistics
{
   using NUMBER = Decimal;
   public class WilcoxonGroupsCollection : GroupsCollection
   {
      public WilcoxonGroupsCollection() : base() { }

      public WilcoxonGroupsCollection(List<Group> groups)
         : base(groups)
      {
         if (groups.Count > 2)
            throw new BiostatisticsException(
               "WilcoxonGroupsCollection has more than two Groups.");
      }

      public override void Add(Group group)
      {
         if (group == null)
            throw new BiostatisticsException(
               "group is a null reference.");

         if (groupsArray == null || k() == 0)
         {
            base.Add(group);
            return;
         }

         if (k() == 1 && group.n() == groupsArray[0].n())
         {
            base.Add(group);
            List<Rank> lstRanks = new List<Rank>();

            // If the difference between a pair of numbers is non-zero,
            // add the difference to lstRanks
            for (Int32 i = 0; i < group.n(); i++)
            {
               if (groupsArray[0][i] - groupsArray[1][i] != 0.0m)
                  lstRanks.Add(new Rank(0, groupsArray[0][i]
                     - groupsArray[1][i], 0.0m));
            }
            iN = lstRanks.Count;

            // Sort the rank objects by the absolute value of their values
            lstRanks.Sort(Rank.CompareRanksByAbsoluteValues);

            // Assign ranks starting at 1
            for (Int32 i = 0; i < lstRanks.Count; i++)
               lstRanks[i] = new Rank(lstRanks[i].iGroup, lstRanks[i].decValue,
                  (NUMBER)(i + 1));

            // Adjust for ties
            iTieAdjustment = Rank.AdjustTies(ref lstRanks);

            // Apply the signs of the differences to the ranks
            for (Int32 i = 0; i < lstRanks.Count; i++)
            {
               if (lstRanks[i].decValue < 0)
                  lstRanks[i] = new Rank(lstRanks[i].iGroup, lstRanks[i].decValue,
                     -1.0m * lstRanks[i].decRank);
            }

            decW = 0.0m;
            decTminus = 0.0m;
            decTplus = 0.0m;

            foreach (Rank rank in lstRanks)
            {
               NUMBER rnk = rank.decRank;
               NUMBER val = rank.decValue;

               if (val > 0.0m)
                  decTplus += rnk;
               else
                  decTminus += -1.0m * rnk;

               decW += rnk;
            }
            decW = DecMath.Abs(decW);



            NUMBER decA = n() * (n() + 1) * (2 * n() + 1);
            NUMBER decB = decA / 6.0m;
            NUMBER decC = ((NUMBER)iTieAdjustment) / 12.0m;
            NUMBER decD = decB - decC;
            decStandardDeviationW = DecMath.Sqrt(decD);

            NUMBER decE = ((NUMBER)iTieAdjustment) / 2.0m;
            NUMBER decF = (decA - decE) / 24.0m;
            decStandardDeviationT = DecMath.Sqrt(decF);

            return;
         }

         if (k() == 1 && group.n() != groupsArray[0].n())
         {
            throw new BiostatisticsException(
               "WilcoxonGroupsCollection Groups must have equal sizes.");
         }

         if (k() > 1)
         {
            throw new BiostatisticsException(
"Addition of Group to WilcoxonGroupsCollection that contains more than 1 Group.");
         }
      }

      public NUMBER CriticalValue()
      {
         NUMBER decT;

         if (groupsArray == null || groupsArray[0] == null || groupsArray[1] == null)
            throw new BiostatisticsException(
               "groupsArray not complete.");

         if (n() < 4 || n() > 100)
            throw new BiostatisticsException(
               "n() outside the range of the critical values table.");

         if (decTplus < decTminus)
            decT = decTplus;
         else
            decT = decTminus;

         if (CriticalValues[n() - 4, 1] < decT)
            throw new BiostatisticsException(
               "p > 0.5");

         if (CriticalValues[n() - 4, 1] == decT)
            return 0.5m;

         Int16 iLastColumn = 3;
         for (; iLastColumn < 9; iLastColumn++)
            if (CriticalValues[n() - 4, iLastColumn] == null)
               break;

         //if (decT <= CriticalValues[n() - 4, iLastColumn - 1])
         //   return 0.001m;

         for (Int16 i = (Int16)(iLastColumn - 1); i > 0; i--)
            if (decT <= CriticalValues[n() - 4, i])
               return alphas[i];

         throw new BiostatisticsException(
            "Error in computation of critical value.");
      }

      public NUMBER MuT()
      {
         if (groupsArray == null || groupsArray[0] == null || groupsArray[1] == null)
            throw new BiostatisticsException(
               "groupsArray not complete.");

         return (n() * (n() + 1)) / 4.0m;
      }

      public Int32 n()
      {
         if (groupsArray == null || groupsArray[0] == null || groupsArray[1] == null)
            throw new BiostatisticsException(
               "groupsArray not complete.");

         return iN;
      }

      public NUMBER p()
      {
         if (groupsArray == null || groupsArray[0] == null || groupsArray[1] == null)
            throw new BiostatisticsException(
               "groupsArray not complete.");

         return Distributions.ProbabilityZ(Zw());
      }

      public NUMBER pUncorrected()
      {
         if (groupsArray == null || groupsArray[0] == null || groupsArray[1] == null)
            throw new BiostatisticsException(
               "groupsArray not complete.");

         return Distributions.ProbabilityZ(ZwUncorrected());
      }

      public NUMBER StandardDeviationW()
      {
         if (groupsArray == null || groupsArray[0] == null || groupsArray[1] == null)
            throw new BiostatisticsException(
               "groupsArray not complete.");

         return decStandardDeviationW;
      }

      public NUMBER StandardDeviationT()
      {
         if (groupsArray == null || groupsArray[0] == null || groupsArray[1] == null)
            throw new BiostatisticsException(
               "groupsArray not complete.");

         return decStandardDeviationT;
      }

      public NUMBER Tminus()
      {
         if (groupsArray == null || groupsArray[0] == null || groupsArray[1] == null)
            throw new BiostatisticsException(
               "groupsArray not complete.");

         return decTminus;
      }

      public NUMBER Tplus()
      {
         if (groupsArray == null || groupsArray[0] == null || groupsArray[1] == null)
            throw new BiostatisticsException(
               "groupsArray not complete.");

         return decTplus;
      }

      public Int32 W()
      {
         if (groupsArray == null || groupsArray[0] == null || groupsArray[1] == null)
            throw new BiostatisticsException(
               "groupsArray not complete.");

         return Convert.ToInt32(decW);
      }

      public NUMBER Zt()
      {
         if (groupsArray == null || groupsArray[0] == null || groupsArray[1] == null)
            throw new BiostatisticsException(
               "groupsArray not complete.");

         NUMBER decA = DecMath.Abs(Tplus() - MuT());
         NUMBER decZt;

         try
         {
            decZt = (decA - 0.5m) / StandardDeviationT();
         }
         catch (Exception e)
         {
            throw new BiostatisticsException(e.Source + ": " + e.Message, e);
         }
         return decZt;
      }

      public NUMBER ZtUncorrected()
      {
         if (groupsArray == null || groupsArray[0] == null || groupsArray[1] == null)
            throw new BiostatisticsException(
               "groupsArray not complete.");

         NUMBER decA = DecMath.Abs(Tplus() - MuT());
         NUMBER decZt;

         try
         {
            decZt = decA / StandardDeviationT();
         }
         catch (Exception e)
         {
            throw new BiostatisticsException(e.Source + ": " + e.Message, e);
         }
         return decZt;
      }

      public NUMBER Zw()
      {
         if (groupsArray == null || groupsArray[0] == null || groupsArray[1] == null)
            throw new BiostatisticsException(
               "groupsArray not complete.");

         NUMBER decA = DecMath.Abs(W()) - 0.5m;
         NUMBER decB = (NUMBER)(n() * (n() + 1) * (2 * n() + 1)) / 6.0m;
         NUMBER decC = DecMath.Sqrt(decB);
         NUMBER decZw;
         try
         {
            decZw = decA / decC;
         }
         catch (Exception e)
         {
            throw new BiostatisticsException(e.Source + ": " + e.Message, e);
         }
         return decZw;
      }

      public NUMBER ZwUncorrected()
      {
         if (groupsArray == null || groupsArray[0] == null || groupsArray[1] == null)
            throw new BiostatisticsException(
               "groupsArray not complete.");

         NUMBER decA = DecMath.Abs(W());
         NUMBER decB = (NUMBER)(n() * (n() + 1) * (2 * n() + 1)) / 6.0m;
         NUMBER decC = DecMath.Sqrt(decB);
         NUMBER decZw;
         try
         {
            decZw = decA / decC;
         }
         catch (Exception e)
         {
            throw new BiostatisticsException(e.Source + ": " + e.Message, e);
         }
         return decZw;
      }

      private NUMBER decW;
      private NUMBER decTplus;
      private NUMBER decTminus;
      private Int32 iTieAdjustment;
      private NUMBER decStandardDeviationW;
      private NUMBER decStandardDeviationT;
      private Int32 iN;

      private readonly NUMBER[] alphas =
      {
         0.0m, 0.5m, 0.2m, 0.1m, 0.05m, 0.02m, 0.01m, 0.005m, 0.001m
      };

      private readonly Int16?[,] CriticalValues = 
      {
         {4, 2, 0, null, null, null, null, null, null},
         {5, 4, 2, 0, null, null, null, null, null},
         {6, 6, 3, 2, 0, null, null, null, null},
         {7, 9, 5, 3, 2, 0, null, null, null},
         {8, 12, 8, 5, 3, 1, 0, null, null},
         {9, 16, 10, 8, 5, 3, 1, 0, null},
         {10, 20, 14, 10, 8, 5, 3, 1, null},
         {11, 24, 17, 13, 10, 7, 5, 3, 0},
         {12, 29, 21, 17, 13, 9, 7, 5, 1},
         {13, 35, 26, 21, 17, 12, 9, 7, 2},
         {14, 40, 31, 25, 21, 15, 12, 9, 4},
         {15, 47, 36, 30, 25, 19, 15, 12, 6},
         {16, 54, 42, 35, 29, 23, 19, 15, 8},
         {17, 61, 48, 41, 34, 27, 23, 19, 11},
         {18, 69, 55, 47, 40, 32, 27, 23, 14},
         {19, 77, 62, 53, 46, 37, 32, 27, 18},
         {20, 86, 69, 60, 52, 43, 37, 32, 21},
         {21, 95, 77, 67, 58, 49, 42, 37, 25},
         {22, 104, 86, 75, 65, 55, 48, 42, 30},
         {23, 114, 94, 83, 73, 62, 54, 48, 35},
         {24, 125, 104, 91, 81, 69, 61, 54, 40},
         {25, 136, 113, 100, 89, 76, 68, 60, 45},
         {26, 148, 124, 110, 98, 84, 75, 67, 51},
         {27, 160, 134, 119, 107, 92, 83, 74, 57},
         {28, 172, 145, 130, 116, 101, 91, 82, 64},
         {29, 185, 157, 140, 126, 110, 100, 90, 71},
         {30, 198, 169, 151, 137, 120, 109, 98, 78},
         {31, 212, 181, 163, 147, 130, 118, 107, 86},
         {32, 226, 194, 175, 159, 140, 128, 116, 94},
         {33, 241, 207, 187, 170, 151, 138, 126, 102},
         {34, 257, 221, 200, 182, 162, 148, 136, 111},
         {35, 272, 235, 213, 195, 173, 159, 146, 120},
         {36, 289, 250, 227, 208, 185, 171, 157, 130},
         {37, 305, 265, 241, 221, 198, 182, 168, 140},
         {38, 323, 281, 256, 235, 211, 194, 180, 150},
         {39, 340, 297, 271, 249, 224, 207, 192, 161},
         {40, 358, 313, 286, 264, 238, 220, 204, 172},
         {41, 377, 330, 302, 279, 252, 233, 217, 183},
         {42, 396, 348, 319, 294, 266, 247, 230, 195},
         {43, 416, 365, 336, 310, 281, 261, 244, 207},
         {44, 436, 384, 353, 327, 296, 276, 258, 220},
         {45, 456, 402, 371, 343, 312, 291, 272, 233},
         {46, 477, 422, 389, 361, 328, 307, 287, 246},
         {47, 499, 441, 407, 378, 345, 322, 302, 260},
         {48, 521, 462, 426, 396, 362, 339, 318, 274},
         {49, 543, 482, 446, 415, 379, 355, 334, 289},
         {50, 566, 503, 466, 434, 397, 373, 350, 304},
         {51, 590, 525, 486, 453, 416, 390, 367, 319},
         {52, 613, 547, 507, 473, 434, 408, 384, 335},
         {53, 638, 569, 529, 494, 454, 427, 402, 351},
         {54, 668, 592, 550, 514, 473, 445, 420, 368},
         {55, 688, 615, 573, 536, 493, 465, 438, 385},
         {56, 714, 639, 595, 557, 514, 484, 457, 402},
         {57, 740, 664, 618, 579, 535, 504, 477, 420},
         {58, 767, 688, 642, 602, 556, 525, 497, 438},
         {59, 794, 714, 666, 625, 578, 546, 517, 457},
         {60, 822, 739, 690, 648, 600, 567, 537, 476},
         {61, 850, 765, 715, 672, 623, 589, 558, 495},
         {62, 879, 792, 741, 697, 646, 611, 580, 515},
         {63, 908, 819, 767, 721, 669, 634, 602, 535},
         {64, 938, 847, 793, 747, 693, 657, 624, 556},
         {65, 968, 875, 820, 772, 718, 681, 647, 577},
         {66, 998, 903, 847, 798, 742, 705, 670, 599},
         {67, 1029, 932, 875, 825, 768, 729, 694, 621},
         {68, 1061, 962, 903, 852, 793, 754, 718, 643},
         {69, 1093, 992, 931, 879, 819, 779, 742, 666},
         {70, 1126, 1022, 960, 907, 846, 805, 767, 689},
         {71, 1159, 1053, 990, 936, 873, 831, 792, 712},
         {72, 1192, 1084, 1020, 964, 901, 858, 818, 736},
         {73, 1226, 1116, 1050, 994, 928, 884, 844, 761},
         {74, 1261, 1148, 1081, 1023, 957, 912, 871, 786},
         {75, 1296, 1181, 1112, 1053, 986, 940, 898, 811},
         {76, 1331, 1214, 1144, 1084, 1015, 968, 925, 836},
         {77, 1367, 1247, 1176, 1115, 1044, 997, 953, 862},
         {78, 1403, 1282, 1209, 1147, 1075, 1026, 980, 889},
         {79, 1440, 1316, 1242, 1179, 1105, 1056, 1010, 916},
         {80, 1478, 1351, 1276, 1211, 1136, 1086, 1039, 943},
         {81, 1516, 1387, 1310, 1244, 1168, 1116, 1036, 971},
         {82, 1554, 1423, 1345, 1277, 1200, 1147, 1099, 999},
         {83, 1593, 1459, 1380, 1311, 1232, 1178, 1129, 1028},
         {84, 1632, 1496, 1415, 1345, 1265, 1210, 1160, 1057},
         {85, 1672, 1533, 1451, 1380, 1298, 1242, 1191, 1086},
         {86, 1712, 1571, 1487, 1415, 1332, 1275, 1223, 1116},
         {87, 1753, 1609, 1524, 1451, 1366, 1308, 1255, 1146},
         {88, 1794, 1648, 1561, 1487, 1400, 1342, 1288, 1177},
         {89, 1836, 1688, 1599, 1523, 1435, 1376, 1321, 1208},
         {90, 1878, 1727, 1638, 1560, 1471, 1410, 1355, 1240},
         {91, 1921, 1767, 1676, 1597, 1507, 1445, 1389, 1271},
         {92, 1964, 1808, 1715, 1635, 1543, 1480, 1423, 1304},
         {93, 2008, 1849, 1755, 1674, 1580, 1516, 1458, 1337},
         {94, 2052, 1891, 1795, 1712, 1617, 1552, 1493, 1370},
         {95, 2097, 1933, 1836, 1752, 1655, 1589, 1529, 1404},
         {96, 2142, 1976, 1877, 1791, 1693, 1626, 1565, 1438},
         {97, 2187, 2019, 1918, 1832, 1731, 1664, 1601, 1472},
         {98, 2233, 2062, 1960, 1872, 1770, 1702, 1638, 1507},
         {99, 2280, 2106, 2003, 1913, 1810, 1740, 1676, 1543},
         {100, 2327, 2151, 2045, 1955, 1850, 1779, 1714, 1578}
      };
   }
}

---