unit MannWhitUUnit;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, LResources, Forms, Controls, Graphics, Dialogs,
  StdCtrls, Buttons, MainUnit, OutPutUnit, FunctionslIB,
  Globals, DataProcs, Math;

type

  { TMannWhitUFrm }

  TMannWhitUFrm = class(TForm)
    GrpIn: TBitBtn;
    GrpOut: TBitBtn;
    DepIn: TBitBtn;
    DepOut: TBitBtn;
    ResetBtn: TButton;
    CancelBtn: TButton;
    ComputeBtn: TButton;
    ReturnBtn: TButton;
    GrpEdit: TEdit;
    DepEdit: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    VarList: TListBox;
    procedure ComputeBtnClick(Sender: TObject);
    procedure DepInClick(Sender: TObject);
    procedure DepOutClick(Sender: TObject);
    procedure FormShow(Sender: TObject);
    procedure GrpInClick(Sender: TObject);
    procedure GrpOutClick(Sender: TObject);
    procedure ResetBtnClick(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end; 

var
  MannWhitUFrm: TMannWhitUFrm;

implementation

{ TMannWhitUFrm }

procedure TMannWhitUFrm.ResetBtnClick(Sender: TObject);
VAR i : integer;
begin
     GrpEdit.Text := '';
     DepEdit.Text := '';
     GrpIn.Visible := true;
     GrpOut.Visible := false;
     DepIn.Visible := true;
     DepOut.Visible := false;
     VarList.Items.Clear;
     for i := 1 to NoVariables do
         VarList.Items.Add(OS3MainFrm.DataGrid.Cells[i,0]);
end;

procedure TMannWhitUFrm.FormShow(Sender: TObject);
begin
     ResetBtnClick(self);
end;

procedure TMannWhitUFrm.DepInClick(Sender: TObject);
VAR index : integer;
begin
     index := VarList.ItemIndex;
     DepEdit.Text := VarList.Items.Strings[index];
     VarList.Items.Delete(index);
     DepIn.Visible := false;
     DepOut.Visible := true;
end;

procedure TMannWhitUFrm.ComputeBtnClick(Sender: TObject);
label cleanup, Check1;
var
   i, j, ind_var, dep_var, min_grp, max_grp, group, total_n : integer;
   NoTies, NoTieGroups, n1, n2, nogroups, largestn : integer;
   NoSelected : integer;
   ColNoSelected : IntDyneVec;
   group_count : IntdyneVec;
   Ranks, X : DblDyneMat;
   RankSums : DblDyneVec;
   TieSum, score, t, SumT, Avg, z, prob, U, U2, SD, Temp : double;
   cellstring, outline : string;

begin
     total_n := 0;
     NoTieGroups := 0;
     NoSelected := 2;
     SumT := 0.0;

    // Check for data
    if (NoVariables < 1) then
    begin
        ShowMessage('ERROR! You must have grid data!');
        exit;
    end;

    // allocate space
    SetLength(ColNoSelected,NoVariables);

    // Get column numbers of the independent and dependent variables
    ind_var := 0;
    dep_var := 0;
    for i := 1 to NoVariables do
    begin
        cellstring := GrpEdit.Text;
        if (cellstring = OS3MainFrm.DataGrid.Cells[i,0]) then ind_var := i;
        cellstring := DepEdit.Text;
        if (cellstring = OS3MainFrm.DataGrid.Cells[i,0]) then dep_var := i;
    end;
    ColNoSelected[0] := ind_var;
    ColNoSelected[1] := dep_var;

    //get minimum and maximum group codes
    min_grp := 10000;
    max_grp := -10000;
    for i := 1 to NoCases do
    begin
        if (not GoodRecord(i,NoSelected,ColNoSelected)) then continue;
        group := round(StrToFloat(Trim(OS3MainFrm.DataGrid.Cells[ind_var,i])));
        if (group < min_grp) then min_grp := group;
        if (group > max_grp) then max_grp := group;
        total_n := total_n + 1;
    end;
    nogroups := max_grp - min_grp + 1;

    // Initialize arrays
    SetLength(RankSums,nogroups);
    SetLength(Ranks,NoCases,2);
    SetLength(X,NoCases,2);
    SetLength(group_count,nogroups);
    for i := 0 to nogroups-1 do
    begin
        group_count[i] := 0;
        RankSums[i] := 0.0;
    end;

    // Setup for printer output
    OutPutFrm.RichEdit.Clear;
    OutPutFrm.RichEdit.Lines.Add('Mann-Whitney U Test');
    OutPutFrm.RichEdit.Lines.Add('See pages 116-127 in S. Siegel: Nonparametric Statistics for the Behavioral Sciences');
    OutPutFrm.RichEdit.Lines.Add('');

    // Get data
    for i := 1 to NoCases do
    begin
        if (not GoodRecord(i,NoSelected,ColNoSelected)) then continue;
        score := StrToFloat(Trim(OS3MainFrm.DataGrid.Cells[dep_var,i]));
        group := round(StrToFloat(Trim(OS3MainFrm.DataGrid.Cells[ind_var,i])));
        group := group - min_grp + 1;
        if (group > 2) then
        begin
            ShowMessage('ERROR! Group codes must be 1 and 2!');
            goto cleanup;
        end;
        group_count[group-1] := group_count[group-1] + 1;
        X[i-1,0] := score;
        X[i-1,1] := group;
    end;

    //Sort all scores in ascending order
    for i := 1 to total_n - 1 do
    begin
        for j := i + 1 to total_n do
        begin
            if (X[i-1,0] > X[j-1,0]) then
            begin
                Temp := X[i-1,0];
                X[i-1,0] := X[j-1,0];
                X[j-1,0] := Temp;
                Temp := X[i-1,1];
                X[i-1,1] := X[j-1,1];
                X[j-1,1] := Temp;
            end;
        end;
    end;

    // Store ranks
    for i := 1 to total_n do
    begin
        Ranks[i-1,0] := i;
        Ranks[i-1,1] := X[i-1,1];
    end;

    //Check for ties in ranks - replace with average rank and calculate
    //T for each tie and sum of the T's
    i := 1;
    while i < total_n do
    begin
        j := i + 1;
        TieSum := 0;
        NoTies := 0;
        while (j < total_n) do
        begin
            if (X[j-1,0] > X[i-1,0]) then goto Check1;
            if (X[j-1,0] = X[i-1,0]) then // match
            begin
                TieSum := TieSum + round(Ranks[j-1,0]);
                NoTies := NoTies + 1;
            end;
            j := j + 1;
        end;
Check1:
        if (NoTies > 0) then //At least one tie found
        begin
            TieSum := TieSum + Ranks[i-1,0];
            NoTies := NoTies + 1;
            Avg := TieSum / NoTies;
            for j := i to i + NoTies - 1 do Ranks[j-1,0] := Avg;
            t := Power(NoTies,3) - NoTies;
            SumT := SumT + t;
            NoTieGroups := NoTieGroups + 1;
            i := i + (NoTies - 1);
        end;
        i := i + 1;
    end; // next i

    // Calculate sum of ranks in each group
    for i := 1 to total_n do
    begin
        group := round(Ranks[i-1,1]);
        RankSums[group-1] := RankSums[group-1] + Ranks[i-1,0];
    end;

    //Calculate U for larger and smaller groups
    n1 := group_count[0];
    n2 := group_count[1];
    if (n1 > n2) then
        U := (n1 * n2) + ((n1 * (n1 + 1)) / 2.0) - RankSums[0]
    else
        U := (n1 * n2) + ((n2 * (n2 + 1)) / 2.0) - RankSums[1];
    U2 := (n1 * n2) - U;
    SD := (n1 * n2 * (n1 + n2 + 1)) / 12.0;
    SD := sqrt(SD);
    if (U2 > U) then z := (U2 - (n1 * n2 / 2)) / SD
    else z := (U - (n1 * n2 / 2)) / SD;
    prob := 1.0 - probz(z);

    //Report results
    OutPutFrm.RichEdit.Lines.Add('     Score     Rank      Group');
    OutPutFrm.RichEdit.Lines.Add('');
    for i := 1 to total_n do
    begin
        outline := format('%10.2f %10.2f %10.0f',
            [X[i-1,0], Ranks[i-1,0], Ranks[i-1,1]]);
        OutPutFrm.RichEdit.Lines.Add(outline);
    end;
    OutPutFrm.RichEdit.Lines.Add('');
    OutPutFrm.RichEdit.Lines.Add('Sum of Ranks in each Group');
    OutPutFrm.RichEdit.Lines.Add('Group   Sum    No. in Group');
    for i := 1 to nogroups do
    begin
        outline := format('%3d  %10.2f %5d', [i+min_grp-1, RankSums[i-1],group_count[i-1]]);
        OutPutFrm.RichEdit.Lines.Add(outline);
    end;
    OutPutFrm.RichEdit.Lines.Add('');
    outline := format('No. of tied rank groups = %3d',[NoTieGroups]);
    OutPutFrm.RichEdit.Lines.Add(outline);
    if (n1 > n2) then largestn := n1
    else largestn := n2;
    if (largestn < 20) then
        outline := format('Statistic U = %8.4f',[U])
    else
    begin
        if (U > U2) then outline := format('Statistic U = %8.4f',[U])
        else outline := format('Statistic U = %8.4f',[U2]);
    end;
    OutPutFrm.RichEdit.Lines.Add(outline);
    outline := format('z Statistic (corrected for ties) = %8.4f, Prob. > z = %6.4f',
                     [z, prob]);
    OutPutFrm.RichEdit.Lines.Add(outline);
    if (n2 < 20) then
    begin
        OutPutFrm.RichEdit.Lines.Add('z test is approximate.  Use tables of exact probabilities in Siegel.');
        OutPutFrm.RichEdit.Lines.Add('(Table J or K, pages 271-277)');
    end;
    OutPutFrm.ShowModal;

    // Clean up the heap
cleanup:
    group_count := nil;
    X := nil;
    Ranks := nil;
    RankSums := nil;
    ColNoSelected := nil;
end;

procedure TMannWhitUFrm.DepOutClick(Sender: TObject);
begin
     VarList.Items.Add(DepEdit.Text);
     DepEdit.Text := '';
     DepIn.Visible := true;
     DepOut.Visible := false;
end;

procedure TMannWhitUFrm.GrpInClick(Sender: TObject);
VAR index : integer;
begin
     index := VarList.ItemIndex;
     GrpEdit.Text := VarList.Items.Strings[index];
     VarList.Items.Delete(index);
     GrpIn.Visible := false;
     GrpOut.Visible := true;
end;

procedure TMannWhitUFrm.GrpOutClick(Sender: TObject);
begin
     VarList.Items.Add(GrpEdit.Text);
     GrpEdit.Text := '';
     GrpIn.Visible := true;
     GrpOut.Visible := false;
end;

initialization
  {$I mannwhituunit.lrs}

end.