)
and
P(F) = P ({THH}) + P ({THT}) + P ({TTH}) + P ({TTT})
= 1
1
1
1
1
8
8
8
8
2
+
+
+
=
Also
E ∩ F = {THH}
with
P(E ∩ F) = P({THH}) = 1
8
Now, suppose we are given that the first coin shows tail, i e F occurs, then what is
the probability of occurrence of E With the information of occurrence of F, we are
sure that the cases in which first coin does not result into a tail should not be considered
while finding the probability of E