G and H are mutually exclusive events. P(A)= 0.5; P(B)=0.3

Explain why this statement must be false: P(B I A)=0.4

Question

G and H are mutually exclusive events. P(A)= 0.5; P(B)=0.3

Explain why this statement must be false: P(B I A)=0.4

agent0smith · Answer

If two events are mutually exclusive, then the probability of one event does NOT depend on the other occurring (or not occurring).

ie

P(B I A)=P(B)
and
P(A | B)=P(A)

anonymous · Answer

why must the following statement be false then?

agent0smith · Answer

Have a look at the probability values they gave you. 

P(B I A)=0.4 and P(B)=0.3

Now compare them to this... P(B I A)=P(B) which is true for mutually exclusive events.

anonymous · Answer

Ah, I see that now! Thank you.

agent0smith · Answer

You're welcome :)