1
0 001
 100
 
© NCERT
not to be republished
PROBABILITY      553
P(E′) = 1 – P(E) = 0 999
P(A|E) = P(Person tested as HIV+ive given that he/she
is actually having HIV)
= 90% 
90
0 9
 100
 
and
P(A|E′) = P(Person tested as HIV +ive given that he/she
is actually not having HIV)
= 1% = 1
100 = 0