100'  NAME--PHICOE
110'
120'  DESCRIPTION--COMPUTES THE VALUE OF THE PHI COEFFICIENT AND
130'  THE NUMBER OF CASES,N, FOR DATA ON TWO VARIABLES, X AND Y,
140'  PRESENTED IN A 2 BY 2 TABLE SUCH AS:
150'                                                   X1         X2
160'                                                   --         --
170'                                             Y1    A          B
180'                                             Y2    C          D
190'
200'  SOURCE--UNKNOWN
210'
220'  INSTRUCTIONS--ENTER DATA IN ORDER A,B,C,D IN A DATA STATEMENT IN
230'  LINE 900.
240'
250'
260'  *  *  *  *  *  *   MAIN PROGRAM  *  *  *  *  *  *  *  *  *
270'
280  READ A,B,C,D
290  LET P=(B*C-A*D)/SQR((A+C)*(B+D)*(A+B)*(C+D))
300  LET N=A+B+C+D
310  PRINT "PHI COEFFICIENT = "P, "N = "N
900  DATA 10,15,10,30
910  END