5 ONERRORGOTO500
10 IFp=<0 ORp>=1 THEN*
20 y=-LN(4*p*(1-p))
30 x=.5824238515E-5+y*(-.104527497E-5+y*(.8360937017E-7+y*(-.3231081277E-8+y*(.3657763036E-10+y*.6936233982E-12))))
40 x=SQR(y*(1.570796288+y*(.03706987906+y*(-.8364353589E-3+y*(-.2250947176E-3+y*(.6841218299E-5+y*x))))))
50 IFp>.5 THENx=-x
80 y=x:RETURN
500 IFERR=1 THENCLS:ONERRORGOTO0
510 sr=1:RESUME80