Suppose we wanted to determine the probability that a randomly chosen person does NOT have blood type O. To answer this question, we must understand the concept of complement events. The comple- ment of an event contains all of the outcomes in a probability distribution that are not in the event. The Complement Rule The sum of the probability of an event and the probability of the event's complement is 1. P(A) +P(not A) = 1 ( 2) Complement Event O 44% not O 56% Examples election, and aand the sty 1. What is the probability that a randomly chosen person does NOT have blood type A? 2. What is the probability that two randomly chosen persons do NOT have blood type A