8999 REM ******* REVISED APRIL, 1972  BY ED BAKER *******
9000 REM ***** PHICOE ***** MATHEMATICS PROGRAM *****
9001 REM ***** VERSION 1 ***** 7/31/69 *****
9002 REM COMPUTERS PHI COEFFICIENT
9003 INPUT'INSTRUCTIONS';A$:IFA$='YES'THENGOSUB9100
9004 INPUT'WHAT ARE YOUR VALUES FOR A,B,C, AND D';A,B,C,D:P=
	(B*C-A*D)/SQR((A+C)*(B+D)*(A+B)*(C+D))
9005 LET N=A+B+C+D
9006 PRINT:PRINT'PHI COEFFICIENT='P,'N='N
9007 PRINT:PRINT:INPUT'AGAIN';A$:IFA$='NO'THEN9999 ELSE 9003
9100 PRINT 'THIS PROGRAM COMPUTES THE VALUE OF THE PHI-COEFFICIENT'
9110 PRINT 'AND THE NUMBER OF CASES, N, FOR DATA ON TWO VARIABLES, X '
9120 PRINT 'AND Y, PRESENTED IN A 2 X 2 TABLE SUCH AS:'
9130 PRINT:PRINT
9140 PRINT'                   X(1)          X(2)'
9150 PRINT
9160 PRINT'         Y(1)       A             B'
9170 PRINT
9180 PRINT'         Y(2)       C             D'
9190 PRINT:PRINT:PRINT
9200 RETURN
9999 END