C PHI 10
C ..................................................................PHI 20
C PHI 30
C SUBROUTINE PHI PHI 40
C PHI 50
C PURPOSE PHI 60
C TO COMPUTE THE PHI COEFFICIENT BETWEEN TWO VARIABLES WHICH PHI 70
C ARE DICHOTOMOUS. PHI 80
C PHI 90
C USAGE PHI 100
C CALL PHI (N,U,V,HU,HV,P,CH,XP,IE) PHI 110
C PHI 120
C DESCRIPTION OF PARAMETERS PHI 130
C N - NUMBER OF OBSERVATIONS PHI 140
C U - INPUT VECTOR OF LENGTH N CONTAINING THE FIRST DICHOTO- PHI 150
C MOUS VARIABLE PHI 160
C V - INPUT VECTOR OF LENGTH N CONTAINING THE SECOND DICHOTO-PHI 170
C MOUS VARIABLE PHI 180
C HU - INPUT NUMERICAL CODE WHICH INDICATES THE HIGHER PHI 190
C CATEGORY OF THE FIRST VARIABLE. ANY OBSERVATION IN PHI 200
C VECTOR U WHICH HAS A VALUE EQUAL TO OR GREATER THAN HU PHI 210
C WILL BE CLASSIFIED IN THE HIGHER CATEGORY. PHI 220
C HV - INPUT NUMERICAL CODE FOR VECTOR V, SIMILAR TO HU PHI 230
C P - PHI COEFFICIENT COMPUTED PHI 240
C CH - CHI-SQUARE COMPUTED AS A FUNCTION OF PHI COEFFICIENT PHI 250
C (DEGREES OF FREEDOM FOR CHI-SQUARE = 1) PHI 260
C XP - COMPUTED VALUE OF THE MAXIMAL PHI COEFFICIENT THAT PHI 270
C CAN BE ATTAINED IN THE PROBLEM PHI 280
C IE - IF IE IS NON-ZERO, SOME CELL IN THE 2 BY 2 TABLE IS PHI 290
C NULL. IF SO, P, CH, AND XP ARE SET TO 10**75. PHI 300
C PHI 310
C REMARKS PHI 320
C VARIABLES U AND V MUST BE SPECIFIED NUMERIC. PHI 330
C THE PHI COEFFICIENT IS A SPECIAL CASE OF THE PHI 340
C PEARSON PRODUCT-MOMENT CORRELATION WHEN BOTH VARIABLES ARE PHI 350
C BINARY. PHI 360
C PHI 370
C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED PHI 380
C NONE PHI 390
C PHI 400
C METHOD PHI 410
C REFER TO P. HORST, 'PYSCHOLOGICAL MEASUREMENT AND PHI 420
C PREDICTION', P. 94 (WADSWORTH, 1966). PHI 430
C PHI 440
C ..................................................................PHI 450
C PHI 460
SUBROUTINE PHI (N,U,V,HU,HV,P,CH,XP,IE) PHI 470
C PHI 480
DIMENSION U(1),V(1) PHI 490
C PHI 500
C CONSTRUCT A 2X2 CONTINGENCY TABLE PHI 510
C PHI 520
IE=0 PHI 530
A=0.0 PHI 540
B=0.0 PHI 550
C=0.0 PHI 560
D=0.0 PHI 570
C PHI 580
DO 40 I=1,N PHI 590
IF(U(I)-HU) 10,25,25 PHI 600
10 IF(V(I)-HV) 15,20,20 PHI 610
15 D=D+1.0 PHI 620
GO TO 40 PHI 630
20 B=B+1.0 PHI 640
GO TO 40 PHI 650
25 IF(V(I)-HV) 30,35,35 PHI 660
30 C=C+1.0 PHI 670
GO TO 40 PHI 680
35 A=A+1.0 PHI 690
40 CONTINUE PHI 700
IF(A) 100,100,41 PHI 710
41 IF(B) 100,100,42 PHI 720
42 IF(C) 100,100,43 PHI 730
43 IF(D) 100,100,44 PHI 740
C PHI 750
C COMPUTE THE PHI COEFFICIENT PHI 760
C PHI 770
44 P=(A*D-B*C)/ SQRT((A+B)*(C+D)*(A+C)*(B+D)) PHI 780
C PHI 790
C COMPUTE CHI-SQURE PHI 800
C PHI 810
T=N PHI 820
CH=T*P*P PHI 830
C PHI 840
C COMPUTE THE MAXIMAL PHI COEFFICIENT PHI 850
C PHI 860
P1=(A+C)/T PHI 870
P2=(B+D)/T PHI 880
P3=(A+B)/T PHI 890
P4=(C+D)/T PHI 900
IF(P1-P2) 75, 45, 45 PHI 910
45 IF(P3-P4) 65, 50, 50 PHI 920
50 IF(P1-P3) 60, 55, 55 PHI 930
55 XP=SQRT((P3/P4)*(P2/P1)) PHI 940
GO TO 95 PHI 950
60 XP=SQRT((P1/P2)*(P4/P3)) PHI 960
GO TO 95 PHI 970
65 IF(P1-P4) 70, 55, 55 PHI 980
70 XP=SQRT((P2/P1)*(P3/P4)) PHI 990
GO TO 95 PHI 1000
75 IF(P3-P4) 90, 80, 80 PHI 1010
80 IF(P2-P3) 60, 85, 85 PHI 1020
85 XP=SQRT((P4/P3)*(P1/P2)) PHI 1030
GO TO 95 PHI 1040
90 IF(P2-P4) 70, 85, 85 PHI 1050
C PHI 1060
95 RETURN PHI 1070
100 IE=1 PHI 1080
P=1.7E38 PHI 1090
CH=1.7E38 PHI 1100
XP=1.7E38 PHI 1110
GO TO 95 PHI 1120
END PHI 1130