Probability

Question 1

How do you know if two events A and B are independent?

Answer 1

If P (A intersection B) = P (A) x P (B) then they are independent

Question 2

What is the addition/or rule?

Answer 2

P(A or B) = P(A) + P(B) - P(A and B)

Question 3

How do you find the probability of P(A\B) i.e. the probability that A happens, given B has happened?

Answer 3

(A and B)/ #B

P(A intersection B)/ P(B)

OR