program chi(input, output);
(* chi: estimates chi squared from degrees of freedom
   Tom Schneider, 1988 *)

label 1; (* end of program *)

const
(* begin module version *)
version = 1.04; (* of chi.p 1994 Sep 5
origin 1988 July 12 *)
(* end module version *)

(* begin module describe.chi *)
(*
name
   chi: estimates chi squared from degrees of freedom

synopsis
   chi(input, output);

files
   input:  degrees of freedom
   output: messages to the user

description
   estimates chi squared, given degrees of freedom.

documentation
   @book{Finberg1978,
   author = "S. Finberg",
   title = "Analysis of Cross Classified Catagorical Data",
   publisher = "MIT Press",
   address = "Cambridge, Mass?",
   year = "1978",
   comment = "from Chip Lawrence, S=Steven"}
   appendix iii

author
   Thomas Dana Schneider

bugs
   it's only an estimate

*)
(* end module describe.chi *)

(* begin module chi.themain *)
procedure themain;
(* the main procedure of the program *)
var
   df: integer; (* degrees of freedom *)
begin
   writeln(output,'chi ',version:4:2);
   writeln(output,'give degrees of freedom: ');
   readln(input,df);

   if df <= 6 then writeln(output,'WARNING: degrees too small');
   if df > 100 then writeln(output,'WARNING: degrees too big');
   writeln(output);
   writeln(output,'NOTE: result is around 1.3% off');
   writeln(output);

   writeln(output,'for           chi squared is');
   writeln(output,'significance  ');
   writeln(output,'0.1           ',sqr(sqrt(df)+0.833):8:2);
   writeln(output,'0.05          ',sqr(sqrt(df)+1.115):8:2);
   writeln(output,'0.025         ',sqr(sqrt(df)+1.365):8:2);
   writeln(output,'0.010         ',sqr(sqrt(df)+1.662):8:2);
   writeln(output,'0.005         ',sqr(sqrt(df)+1.867):8:2);

end;
(* end module chi.themain *)

begin
   themain;
1: end.