CBSE Class 12science  Bayes' Theorem Videos
Bayes' Theorem: Exam Prep Strategies
This video covers partition of a sample space, law of total probability and Bayes Theorem.
 bag 1 contains 8 red and 2 black balls. bag 2 contains 7 red and 5 Black balls. one of the bags is chosen at random and a ball is drawn from it, which is found to be black. find the probability that the ball is drawn from bag 1.
 Two urns contains 1 white,6 red and 4 white,3 red balls. One of t 3 he urn is selected at random and a ball is drawn from it. Find: (1) The probability of drawing a red ball. (ii) The probability of drawing the ball from the first urn if b all drawn is red.

Pl ans
 State Bayes’ theorem.
 Define posteriori probability
 A doctor is to visit a patient. From the past experience, it is known that the probabilities that he will come by train, bus, and scooter or by other means of transport are respectively 0.3, 0.2, 0.1 and 0.4. The probabilities that he will be late are_{}, if he comes by train, bus and scooter respectively, but if he comes by other means of transport, then he will not be late. When he arrives, he is late. What is the probability that he comes by scooter? What is your opinion about being 'late'? Which life skills a person lacks by being 'late'?
 A manufacturer has three machine operators A, B and C. The first operator A produces 1% defective items, where as the other two operators B and C produce 5% and 7% defective items respectively. A is on the job for 50% of the time, B is on the job for 30% of the time and C is on the job for 20% of the time. A defective item is produced, what is the probability that it was produced by B? A manufacturer knows that the item is defective; even then he sells it in the market. Is he doing the right thing? Which life skill is he lacking?
 In answering a question on a multiple choice test, a student either knows the answer or guesses. Let 3/4 be the probability that he knows the answer and 1/4 be the probability that he guesses. Assuming that a student who guesses at the answer will be correct with probability 1/4 . What is the probability that the student knows the answer given that he answered it correctly?
 An urn contains five balls. Two balls are drawn and found to be white. Find the probability that all the balls are white.
 Define random variable.