5 * Revision 1.1.1.1 1996/04/01 15:02:42 mclareni
11 C THIS ROUTINE COMPUTES THE INVERSE OF THE DISTRIBUTION
12 C FUNCTION OF THE STUDENT DISTRIBUTION WITH N DEGREES OF FREEDOM.
13 C Q=PROBABILITY AT WHICH THE FUNCTION IS INVERTED,
14 C N=INTEGER GREATER THAN ZERO.
15 C THE ROUTINE WAS WRITTEN BY G.W.HILL IN ALGOL
16 C C.A.C.M. ALGORITHM 396
17 C AT LEAST 6 SIGNIFICANT FIGURES ARE CORRECT.
21 IF(Q .GE. 0.5) GO TO 1
26 2 IF(P .LE. 0. .OR. P .GT. 1.) GO TO 20
29 STUDIN=PP/SQRT(1.-PP*PP)*RL
31 3 IF(N .GT. 2) GO TO 4
32 STUDIN=SQRT(2./(P*(2.-P))-2.)*RL
37 C=((20700.*A/B-98.)*A-16.)*A+96.36
38 D=((94.5/(B+C)-3.)/B+1.)*SQRT(A*HP)*RN
41 IF(Y .LE. 0.05+A) GO TO 5
45 IF(N .GE. 5) C=C+0.3*(RN-4.5)*(X+0.6)
46 C=(((0.05*D*X-5.)*X-7.)*X-2.)*X+B+C
47 Y=(((((0.4*Y+6.3)*Y+36.)*Y+94.5)/C-Y-3.)/B+1.)*X
49 IF(Y .LE. 0.002) Y=0.5*Y*Y+Y
50 IF(Y .GT. 0.002) Y=EXP(Y)-1.
52 5 Y=((1./(((RN+6.)/(RN*Y)-0.089*D-0.822)*(RN+2.)*3.)+0.5/(RN+4.))*Y-
53 11.)*(RN+1.)/(RN+2.)+1./Y
54 6 STUDIN=SQRT(RN*Y)*RL
59 7 FORMAT(/10X,'DEGREE OF FREEDOM N=',I5,' IN STUDIN ILLEGAL'/)
60 8 FORMAT(/10X,'ARGUMENT Q=',E15.5,' IN STUDIN ILLEGAL'/)