MacWorld 1997 September/Macworld (1997-09).dmg/Serious Software/Cherwell Scientific Demos/pro Fit/pro Fit 5.0 demo (fpu).sea/pro Fit 5.0 demo (fpu)/Examples/Programming - intro/ChiSquared

Text File | 1996-03-30 | 1KB | 40 lines

{ A simple example program for calculating the sum of the squared differences }
{ of two columns in a data window. It shows how to use the Input command }
{ to bring up pop-up menus and checkboxes. }
{ To use the program, choose "Add to Menu" from the Misc menu to compile it }
{ Then open a data window (if none is open). Then run the program by choosing "Chi_squared" }
{ from the misc menu. }

program Chi_squared;

var i, count:integer;    { our global variables }
            num:extended;
            y1c,y2c:integer;
            norm:boolean;

procedure initialize;
{ this procedure is called once, when the program is compiled. Use it for setting default values }
begin
    y1c:=1;y2c:=2;norm:=0;
end;

begin
  Input('$Cy1 Column',y1c,'$Cy2 Column',y2c,'$XDivide result by number of points',norm);
  { $C tells Input to show a popup with all columns, $X a checkbox }
  num := 0;
  count := 0;
  for i:=1 to NrRows do
  begin
        if DataOK(i,y1c) and DataOK(i,y2c) then   { if data in both columns }
        begin
                num := num+sqr(data[i,y1c] - data[i,y2c]);
                count := count+1;
        end;
    end;
  if norm then begin
    writeln('#points = ',count);
    writeln('Chi-squared divided by #points = ',num/count)
  end else
    writeln('Chi-squared = ',num)
end;