190 likes | 293 Views
12.3 – Conditional Probability. Given that A and B are dependent events, the conditional probability of an event B , given that event A has already occurred, is P( B | A ) = P( A and B ) P( A ).
E N D
Given that A and B are dependent events, the conditional probability of an event B, given that event A has already occurred, is P(B|A) = P(A and B) P(A)
Given that A and B are dependent events, the conditional probability of an event B, given that event A has already occurred, is P(B|A) = P(A and B) P(A) Ex. 1 If a die is rolled, what is the probability that a 3 was rolled given that the number is odd
Given that A and B are dependent events, the conditional probability of an event B, given that event A has already occurred, is P(B|A) = P(A and B) P(A) Ex. 1 If a die is rolled, what is the probability that a 3 was rolled given that the number is odd P(3|odd)
Given that A and B are dependent events, the conditional probability of an event B, given that event A has already occurred, is P(B|A) = P(A and B) P(A) Ex. 1 If a die is rolled, what is the probability that a 3 was rolled given that the number is odd P(3|odd) = P(odd and 3)
Given that A and B are dependent events, the conditional probability of an event B, given that event A has already occurred, is P(B|A) = P(A and B) P(A) Ex. 1 If a die is rolled, what is the probability that a 3 was rolled given that the number is odd P(3|odd) = P(odd and 3) P(odd)
Given that A and B are dependent events, the conditional probability of an event B, given that event A has already occurred, is P(B|A) = P(A and B) P(A) Ex. 1 If a die is rolled, what is the probability that a 3 was rolled given that the number is odd P(3|odd) = P(odd and 3) P(odd)
Given that A and B are dependent events, the conditional probability of an event B, given that event A has already occurred, is P(B|A) = P(A and B) P(A) Ex. 1 If a die is rolled, what is the probability that a 3 was rolled given that the number is odd P(3|odd) = P(odd and 3) P(odd) = 1/6
Given that A and B are dependent events, the conditional probability of an event B, given that event A has already occurred, is P(B|A) = P(A and B) P(A) Ex. 1 If a die is rolled, what is the probability that a 3 was rolled given that the number is odd P(3|odd) = P(odd and 3) P(odd) = 1/6 1/2
Given that A and B are dependent events, the conditional probability of an event B, given that event A has already occurred, is P(B|A) = P(A and B) P(A) Ex. 1 If a die is rolled, what is the probability that a 3 was rolled given that the number is odd P(3|odd) = P(odd and 3) P(odd) = 1/6 = 1/3 1/2
Ex. 2 Find the probability that a test subject stayed healthy, given that he or she used an experimental drug.
Ex. 2 Find the probability that a test subject stayed healthy, given that he or she used an experimental drug. Total = 4000
Ex. 2 Find the probability that a test subject stayed healthy, given that he or she used an experimental drug. Total = 4000 P(H|D)
Ex. 2 Find the probability that a test subject stayed healthy, given that he or she used an experimental drug. Total = 4000 P(H|D) = P(H and D)
Ex. 2 Find the probability that a test subject stayed healthy, given that he or she used an experimental drug. Total = 4000 P(H|D) = P(H and D) P(D)
Ex. 2 Find the probability that a test subject stayed healthy, given that he or she used an experimental drug. Total = 4000 P(H|D) = P(H and D) P(D) = 800/4000
Ex. 2 Find the probability that a test subject stayed healthy, given that he or she used an experimental drug. Total = 4000 P(H|D) = P(H and D) P(D) = 800/4000 2400/4000
Ex. 2 Find the probability that a test subject stayed healthy, given that he or she used an experimental drug. Total = 4000 P(H|D) = P(H and D) P(D) = 800/4000 = 800/2400 2400/4000
Ex. 2 Find the probability that a test subject stayed healthy, given that he or she used an experimental drug. Total = 4000 P(H|D) = P(H and D) P(D) = 800/4000= 800/2400= 1/3 2400/4000