In: Statistics and Probability
4.Consider events A and B, neither of which are impossible events. Prove the following
statements.
A)? ? ? = 1 − ?(?|?)
B)If ? ? ? ? = ? ? ∩ ? , then A and B must be independent events.
Question 4
Two events are A and B, neither of which are impossible events.
Question (A)
We have to prove

Now, we see


By definition of conditional probability,





Hence Proved.
Question (B)
If A and B are independent events, it means that the occurrence of A is independent of the occurrence of B.
In probability terms, it means


Now, it is given


By definition of conditional probability, this becomes

Hence proved, A and B must be independent.