800'  NAME--F-TEST
810'
820'  DESCRIPTION--GIVES APPROXIMATE PROBABILITY THAT AN F RANDOM
830'  VARIABLE EXCEEDS F, BASIC ON N AND D DEGREES OF FREEDOM.
840'
850'  SOURCE--PREPARED BY T. E. KURTZ FROM A SUBROUTINE PREPARED BY
860'  V. E. MCGEE (21 APRIL 1969).
870'
880'  INSTRUCTIONS--THIS PROGRAM IS TO BE USED AS A SUBROUTINE AND
890'  F,N, AND D MUST BE SPECIFIED BEFORE IT IS CALLED.
900'
910'
920'  *  *  *  *  *  *  *   MAIN PROGRAM  *  *  *  *  *  *  *  *  *
930'
940  DEF FNP(N,D,F)
950   IF F >= 1 THEN 980
960   LET FNP = 1 - FNP(D,N,1/F)
970   GO TO 1060
980   LET Z1 = 2/(9*N)
990   LET Z2 = 2/(9*D)
1000   LET Z = ABS((1-Z2)*F^(.33333333)-1+Z1)
1010   LET Z = Z/SQR(Z2*F^(.66666667)+Z1)
1020   IF D >= 4 THEN 1040
1030   LET Z = Z*(1+.08*Z^4/D^3)
1040   LET Z = (1+Z*(.196854+Z*(.115194+Z*(.000344+Z*.019527))))^4
1050   LET FNP = .5/Z
1060  FNEND