MaN)Random variable Review of probability and random variables Two events a and B Conditional probability P(aB) Joint probability P(AB=P(AP(BA=P(BP(AB) A and b are independent iff P(AB=P(APB) >Let A,j=1, 2, n be mutually exclusive events with A∩4=②v≠,U4=92. Then for any event B, we have P(B)=∑P(B∩A) ∑P(BlA)P(A) Communications EngineeringCommunications Engineering 9 Random variable Review of probability and random variables ➢ Two events A and B ➢ Conditional probability P(A|B) ➢ Joint probability P(AB)=P(A)P(B|A)=P(B)P(A|B) ➢ A and B are independent iff P(AB)=P(A)P(B) ➢ Let be mutually exclusive events with . Then for any event , we have Aj , j =1,2,  ,n =    i =  i Aj  Ai , i j, A B