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Chapter 4 – Probability and Counting Rules section 4.2 – Addition Rules for Probability. Addition Rules for Probability. Mutually Exclusive two events are mutually exclusive if they cannot occur at the same time (they have no outcomes in common ).
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Chapter 4 – Probability and Counting Rulessection 4.2 – Addition Rules for Probability
Addition Rules for Probability Mutually Exclusive two events are mutually exclusive if they cannot occur at the same time (they have no outcomes in common). Which of the following are mutually exclusive? • getting an odd number and getting an even? • getting a 3 and getting an odd? • getting an odd and getting a number less than 4?
Addition Rules for Probability Addition Rule 1 • When two events are mutually exclusive, the probability that A or B will occur is • P(A or B) = P(A) + P(B) • At a political rally, there are 20 Republicans, 13 Democrats and 6 Independents. If a person is selected at random, what is the probability that he or she is either a Republican or Democrat?
Addition Rules for Probability Addition Rule 2 • When two events are not mutually exclusive, then • P(A or B) = P(A) + P(B) – P(A and B) • On New Year’s Eve, the probability of a person’s driving while intoxicated is 0.32, the probability of a person having an driving accident is 0.09, and the probability of a person having a driving accident while intoxicated is 0.06. • What is the probability of a person’s driving while intoxicated or having a driving accident.
Addition Rules for Probability turn to page 205 • try number 11 in your notes • try number 13
Practice • In class - • p 187 # 2 – 26 even