Курсовой проект групп 3341 и 3382 / DMCore / ContingencyTables

unit ContingencyTables;

interface

uses
dmmTypes,
Statistics,
Utils;

function chiSquared(matrix : D2DArray; yates : boolean) : double;
function chiVal(matrix :D2DArray; useYates : boolean) : double ;
function chiCell(freq : double; expected : double; yates : boolean) : double;

implementation

function chiSquared(matrix : D2DArray; yates : boolean) : double;
var
df : integer;
begin
df := (length(matrix) - 1) * (length(matrix[0]) - 1);
result := Statistics.chiSquaredProbability(chiVal(matrix, yates), df);
end;

function chiVal(matrix :D2DArray; useYates : boolean) : double ;
var
df, nrows, ncols, row, col : integer;
rtotal, ctotal : DArray;
expect, chival, n : double;
yates : boolean;
begin
expect := 0;
chival := 0;
n := 0;
yates := true;

nrows := length(matrix);
ncols := length(matrix[0]);
SetLength(rtotal, nrows);
SetLength(ctotal, ncols);

row := 0;
while ( row < nrows ) do
begin
col := 0;
while ( col < ncols) do
begin
rtotal[row] := rtotal[row] + matrix[row][col];
ctotal[col] := ctotal[col] + matrix[row][col];
n := n + matrix[row][col];
inc(col)
end;
inc(row);
end;
df := (nrows - 1)*(ncols - 1);
if ((df > 1) or (not useYates)) then
yates := false
else
if (df <= 0) then
begin
result := 0;
exit;
end;
chival := 0.0;

row := 0;
while ( row < nrows) do
begin
if (Utils.gr(rtotal[row], 0)) then
begin
col := 0;
while ( col < ncols) do
begin
if (Utils.gr(ctotal[col], 0)) then
begin
expect := (ctotal[col] * rtotal[row]) / n;
chival := chival + chiCell (matrix[row][col], expect, yates);
end;
inc(col);
end;
end;
inc(row);
end;
result := chival;
end;

function chiCell(freq : double; expected : double; yates : boolean) : double;
var
diff : double;
begin
if (Utils.smOrEq(expected, 0)) then
begin
result := 0;
exit;
end;

diff := abs(freq - expected);
if (yates) then
begin
diff := diff - 0.5;

if (diff < 0) then diff := 0;
end;

result:= (diff * diff / expected);
end;

end.