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lazarus-ccr/applications/lazstats/source_orig/ttestunit.pas

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unit TtestUnit;
{$mode objfpc}{$H+}
interface
uses
Classes, SysUtils, FileUtil, LResources, Forms, Controls, Graphics, Dialogs,
ExtCtrls, StdCtrls, MainUnit, Globals, FunctionsLib, OutPutUnit, DataProcs;
type
{ TTtestFrm }
TTtestFrm = class(TForm)
RadioGroup3: TRadioGroup;
ResetBtn: TButton;
CancelBtn: TButton;
ComputeBtn: TButton;
ReturnBtn: TButton;
CorBetweenLabel: TLabel;
Cor12: TEdit;
CInterval: TEdit;
Grp: TEdit;
GroupCodeBtn: TRadioButton;
Label1: TLabel;
Memo1: TMemo;
Var2: TEdit;
Var1: TEdit;
FirstVarLabel: TLabel;
GrpLabel: TLabel;
SecdVarLabel: TLabel;
ListBox1: TListBox;
SelVarLabel: TLabel;
N2: TEdit;
N1: TEdit;
SampSize2Label: TLabel;
SampSize1Label: TLabel;
SD2: TEdit;
SD1: TEdit;
SD2Label: TLabel;
SD1Label: TLabel;
Mean2: TEdit;
Mean1: TEdit;
Mean2Label: TLabel;
Mean1Label: TLabel;
Panel1: TPanel;
Panel2: TPanel;
RadioGroup1: TRadioGroup;
RadioGroup2: TRadioGroup;
procedure ComputeBtnClick(Sender: TObject);
procedure FormShow(Sender: TObject);
procedure ListBox1Click(Sender: TObject);
procedure RadioGroup1Click(Sender: TObject);
procedure RadioGroup2Click(Sender: TObject);
procedure ResetBtnClick(Sender: TObject);
private
{ private declarations }
independent : boolean;
griddata : boolean;
public
{ public declarations }
end;
var
TtestFrm: TTtestFrm;
implementation
{ TTtestFrm }
procedure TTtestFrm.ResetBtnClick(Sender: TObject);
VAR i : integer;
begin
RadioGroup1.ItemIndex := 0;
RadioGroup2.ItemIndex := 0;
Panel1.Visible := false;
Panel2.Visible := true;
ListBox1.Clear;
Var1.Text := '';
Var2.Text := '';
Mean1.Text := '';
Mean2.Text := '';
SD1.Text := '';
SD2.Text := '';
N1.Text := '';
N2.Text := '';
Cor12.Text := '';
independent := true;
griddata := false;
CorBetweenLabel.Visible := false;
Cor12.Visible := false;
GroupCodeBtn.Checked := false;
Grp.Text := '';
for i := 1 to NoVariables do
ListBox1.Items.Add(OS3MainFrm.DataGrid.Cells[i,0]);
GrpLabel.Visible := false;
Grp.Visible := false;
Grp.Text := '';
end;
procedure TTtestFrm.FormShow(Sender: TObject);
begin
ResetBtnClick(self);
end;
procedure TTtestFrm.ComputeBtnClick(Sender: TObject);
var
M1, M2, Dif, stddev1, stddev2, r12, z, stderr1, stderr2 : double;
tequal, tunequal, cov12, lowci, hici, F, Fp, df1, df2 : double;
tprobability, zprobability, stderrt, stderrz, value1, value2 : double;
variance1, variance2, pooled, sedif, df, ConfInt, tconfint : double;
i, j, v1, v2, ncases1, ncases2, NoSelected : integer;
group, min, max : integer;
ColNoSelected : IntDyneVec;
response, cellstring, label1Str, label2Str, outline : string;
begin
SetLength(ColNoSelected,NoVariables);
ncases1 := 0;
ncases2 := 0;
variance1 := 0.0;
variance2 := 0.0;
M1 := 0.0;
M2 := 0.0;
Dif := 0.0;
r12 := 0.0;
v1 := 0;
v2 := 0;
stddev1 := 0.0;
stddev2 := 0.0;
ConfInt := (100.0 - StrToFloat(CInterval.Text)) / 2.0 ;
ConfInt := (100.0 - ConfInt) / 100.0; // one tail
if independent then Var2.Text := Grp.Text;
if griddata then // data read from grid
begin
for i := 1 to NoVariables do
begin
if Var1.Text = OS3MainFrm.DataGrid.Cells[i,0] then
begin
v1 := i;
ColNoSelected[0] := i;
label1Str := Var1.Text;
end;
if Var2.Text = OS3MainFrm.DataGrid.Cells[i,0] then
begin
v2 := i;
ColNoSelected[1] := i;
label2Str := Var2.Text;
end;
end; // next variable
ncases1 := 0;
ncases2 := 0;
NoSelected := 2;
M1 := 0.0;
M2 := 0.0;
variance1 := 0.0;
variance2 := 0.0;
r12 := 0.0;
if not independent then // correlated data
begin
for i := 1 to NoCases do
begin
if not GoodRecord(i,NoSelected,ColNoSelected) then continue;
ncases1 := ncases1 + 1;
value1 := StrToFloat(Trim(OS3MainFrm.DataGrid.Cells[v1,i]));
value2 := StrToFloat(Trim(OS3MainFrm.DataGrid.Cells[v2,i]));
M1 := M1 + value1;
M2 := M2 + value2;
variance1 := variance1 + (value1 * value1);
variance2 := variance2 + (value2 * value2);
r12 := r12 + value1 * value2;
end;
ncases2 := ncases1;
variance1 := variance1 - ((M1 * M1) / ncases1);
variance1 := variance1 / (ncases1 - 1);
stddev1 := sqrt(variance1);
variance2 := variance2 - ((M2 * M2) / ncases2);
variance2 := variance2 / (ncases2 - 1);
stddev2 := sqrt(variance2);
r12 := r12 - ((M1 * M2) / ncases1);
r12 := r12 / (ncases1 - 1);
cov12 := r12;
r12 := r12 / (stddev1 * stddev2);
M1 := M1 / ncases1;
M2 := M2 / ncases2;
Dif := M1 - M2;
end; //if not independent
if independent then
begin
if GroupCodeBtn.Checked then
begin
response := InputBox('Group 1','Enter the code for group 1','1');
min := StrToInt(response);
response := InputBox('Group 2','Enter the code for group 2','2');
max := StrToInt(response);
end
else begin
min := round(StrToFloat(Trim(OS3MainFrm.DataGrid.Cells[v2,1])));
max := min;
end;
for i := 2 to NoCases do
begin
if not GoodRecord(i,NoSelected,ColNoSelected) then continue;
group := round(StrToFloat(Trim(OS3MainFrm.DataGrid.Cells[v2,i])));
if GroupCodeBtn.Checked = false then
begin
if group < min then min := group;
if group > max then max := group;
end;
end;
for i := 1 to NoCases do
begin
if not GoodRecord(i,NoSelected,ColNoSelected) then continue;
value1 := StrToFloat(Trim(OS3MainFrm.DataGrid.Cells[v1,i]));
value2 := StrToFloat(Trim(OS3MainFrm.DataGrid.Cells[v2,i]));
group := round(value2);
if group = min then
begin
M1 := M1 + value1;
variance1 := variance1 + (value1 * value1);
ncases1 := ncases1 + 1;
end
else if group = max then
begin
M2 := M2 + value1;
variance2 := variance2 + (value1 * value1);
ncases2 := Ncases2 + 1;
end;
end; // next case
variance1 := variance1 - ((M1 * M1) / ncases1);
variance1 := variance1 / (ncases1 - 1);
stddev1 := sqrt(variance1);
variance2 := variance2 - ((M2 * M2) / ncases2);
variance2 := variance2 / (ncases2 - 1);
stddev2 := sqrt(variance2);
M1 := M1 / ncases1;
M2 := M2 / ncases2;
Dif := M1 - M2;
Label1Str := format('Group %d',[min]);
Label2Str := format('Group %d',[max]);
end; // if independent data
end; // if reading grid data
if not griddata then // data read from form
begin
M1 := StrToFloat(Mean1.Text);
M2 := StrToFloat(Mean2.Text);
stddev1 := StrToFloat(SD1.Text);
stddev2 := StrToFloat(SD2.Text);
ncases1 := round(StrToFloat(N1.Text));
ncases2 := round(StrToFloat(N2.Text));
variance1 := stddev1 * stddev1;
variance2 := stddev2 * stddev2;
Label1Str := 'Group 1';
Label2Str := 'Group 2';
Dif := M1 - M2;
if not independent then
begin
r12 := StrToFloat(Cor12.Text);
cov12 := r12 * stddev1 * stddev2;
end;
end;
// Initialize output form
OutPutFrm.RichEdit.Clear;
OutPutFrm.RichEdit.Lines.Add('COMPARISON OF TWO MEANS');
OutPutFrm.RichEdit.Lines.Add('');
// OutPutFrm.RichEdit.ParaGraph.Alignment := taLeftJustify;
// Calculate pooled and independent t and z values and test statistic
if independent then
begin
stderr1 := sqrt(variance1 / ncases1);
Stderr2 := sqrt(variance2 / ncases2);
OutPutFrm.RichEdit.Lines.Add('Variable Mean Variance Std.Dev. S.E.Mean N');
outline := format('%-10s%8.2f %8.2f %8.2f %8.2f %d',
[Label1Str,M1, variance1, stddev1, stderr1, ncases1]);
OutPutFrm.RichEdit.Lines.Add(outline);
outline := format('%-10s%8.2f %8.2f %8.2f %8.2f %d',
[Label2Str, M2, variance2, stddev2, stderr2, ncases2]);
OutPutFrm.RichEdit.Lines.Add(outline);
pooled := ((ncases1-1) * variance1) + ((ncases2-1) * variance2);
pooled := pooled / (ncases1 + ncases2 - 2);
pooled := pooled * ( 1.0 / ncases1 + 1.0 / ncases2);
sedif := sqrt(pooled);
tequal := dif / sedif;
df := ncases1 + ncases2 - 2;
tprobability := probt(tequal,df);
if RadioGroup3.ItemIndex = 1 then tprobability := 0.5 * tprobability;
outline := format('Assuming = variances, t = %8.3f with probability = %6.4f and %3.0f degrees of freedom',
[tequal, tprobability, df]);
OutPutFrm.RichEdit.Lines.Add(outline);
outline := format('Difference = %8.2f and Standard Error of difference = %8.2f',
[dif, sedif]);
OutPutFrm.RichEdit.Lines.Add(outline);
tconfint := inverset(ConfInt,df);
lowci := dif - tconfint * sedif;
hici := dif + tconfint * sedif;
outline := format('Confidence interval = (%8.2f,%8.2f)',[lowci,hici]);
OutPutFrm.RichEdit.Lines.Add(outline);
// now for unequal variances
sedif := sqrt((variance1 / ncases1) + (variance2 / ncases2));
tunequal := dif / sedif;
df := sqr((variance1 / ncases1) + (variance2 / ncases2));
df := df / (sqr(variance1 / ncases1) / (ncases1 - 1) +
sqr(variance2 / ncases2) / (ncases2 - 1) );
tprobability := probt(tequal,df);
if RadioGroup3.ItemIndex = 1 then tprobability := 0.5 * tprobability;
outline := format('Assuming unequal variances, t = %8.3f with probability = %6.4f and %5.2f degrees of freedom',
[tunequal, tprobability, df]);
OutPutFrm.RichEdit.Lines.Add(outline);
outline := format('Difference = %8.2f and Standard Error of difference = %8.2f',
[dif, sedif]);
OutPutFrm.RichEdit.Lines.Add(outline);
tconfint := inverset(ConfInt,df);
lowci := dif - tconfint * sedif;
hici := dif + tconfint * sedif;
outline := format('Confidence interval = (%8.2f,%8.2f)',[lowci,hici]);
OutPutFrm.RichEdit.Lines.Add(outline);
df1 := ncases1 - 1;
df2 := ncases2 - 1;
if variance1 > variance2 then
begin
F := variance1 / variance2;
Fp := probf(F,df1,df2);
end
else
begin
F := variance2 / variance1;
Fp := probf(F,df2,df1);
end;
outline := format('F test for equal variances = %8.3f, Probability = %6.4f',
[F, fp]);
OutPutFrm.RichEdit.Lines.Add(outline);
end
else
begin // dependent t test
stderr1 := sqrt(variance1 / ncases1);
Stderr2 := sqrt(variance2 / ncases2);
OutPutFrm.RichEdit.Lines.Add('Variable Mean Variance Std.Dev. S.E.Mean N');
outline := format('%-10s%8.2f %8.2f %8.2f %8.2f %d',
[Label1Str ,M1, variance1, stddev1, stderr1, ncases1]);
OutPutFrm.RichEdit.Lines.Add(outline);
outline := format('%-10s%8.2f %8.2f %8.2f %8.2f %d',
[Label2Str,M2, variance2, stddev2, stderr2, ncases2]);
OutPutFrm.RichEdit.Lines.Add(outline);
sedif := variance1 + variance2 - (2.0 * cov12);
sedif := sqrt(sedif / ncases1);
tequal := Dif / sedif;
df := ncases1 - 1;
tprobability := probt(tequal,df);
outline := format('Assuming dependent samples, t = %8.3f with probability = %6.4f and %3.0f degrees of freedom',
[tequal, tprobability, df]);
OutPutFrm.RichEdit.Lines.Add(outline);
outline := format('Correlation between %s and %s = %6.3f',
[Label1Str,Label2Str,r12]);
OutPutFrm.RichEdit.Lines.Add(outline);
outline := format('Difference = %8.2f and Standard Error of difference = %8.2f',
[dif, sedif]);
OutPutFrm.RichEdit.Lines.Add(outline);
tconfint := inverset(ConfInt,df);
lowci := dif - tconfint * sedif;
hici := dif + tconfint * sedif;
outline := format('Confidence interval = (%8.2f,%8.2f)',
[lowci,hici]);
OutPutFrm.RichEdit.Lines.Add(outline);
tequal := variance1 - variance2;
tequal := tequal / sqrt( (4 * variance1 * variance2)/(ncases1 - 2) *
(1.0 - sqr(r12)) );
df := ncases1 - 2;
tprobability := probt(tequal,df);
outline := format('t for test of equal variances = %8.3f with probability = %6.4f',
[tequal,tprobability]);
OutPutFrm.RichEdit.Lines.Add(outline);
end;
OutPutFrm.ShowModal();
ColNoSelected := nil;
// TtestFrm.Hide;
end;
procedure TTtestFrm.ListBox1Click(Sender: TObject);
VAR index : integer;
begin
index := ListBox1.ItemIndex;
if not independent then
begin
if Var1.Text <> '' then Var2.Text := ListBox1.Items.Strings[index]
else Var1.Text := ListBox1.Items.Strings[index];
end;
if independent then
begin
if Var1.Text <> '' then Grp.Text := ListBox1.Items.Strings[index]
else Var1.Text := ListBox1.Items.Strings[index];
end;
end;
procedure TTtestFrm.RadioGroup1Click(Sender: TObject);
VAR index : integer;
begin
index := RadioGroup1.ItemIndex;
if index = 0 then
begin
Panel2.Visible := true;
Panel1.Visible := false;
griddata := false;
end
else
begin
Panel1.Visible := true;
Panel2.Visible := false;
griddata := true;
if RadioGroup2.ItemIndex = 1 then
begin
SecdVarLabel.Visible := true;
Var2.Visible := true;
Grp.Visible := false;
GrpLabel.Visible := false;
end
else
begin
SecdVarLabel.Visible := false;
Var2.Visible := false;
Grp.Visible := true;
GrpLabel.Visible := true;
end;
end;
end;
procedure TTtestFrm.RadioGroup2Click(Sender: TObject);
VAR index : integer;
begin
index := RadioGroup2.ItemIndex;
if index = 0 then
begin
independent := true;
CorBetweenLabel.Visible := false;
Cor12.Visible := false;
Grp.Visible := true;
GrpLabel.Visible := true;
GroupCodeBtn.Visible := true;
SecdVarLabel.Visible := false;
Var2.Visible := false;
end
else
begin
independent := false;
CorBetweenLabel.Visible := true;
Cor12.Visible := true;
GrpLabel.Visible := false;
Grp.Visible := false;
GroupCodeBtn.Visible := false;
SecdVarLabel.Visible := true;
Var2.Visible := true;
end;
end;
initialization
{$I ttestunit.lrs}
end.