Unformatted text preview: conditional probabilities in the tree. q༇ Step 3: Add the probabilities of the sub events of step 1. PROBLEM 2 v༇ Probability that it will rain tomorrow if it rains today is 0.8. v༇ Probability that it will rain tomorrow if it does not rains today is 0.1. v༇ The probability that it will rain today is 0.6. q༇ What is the chance that it will rain tomorrow? ü༏ Draw the decision tree first? PRACTICE PROBLEM 1 v༇ A fair die is thrown twice. Calculate: q༇ P(least one of the throws is a 3)? q༇ P(sum of the throws equals 4 given at least one of the throws is a 3)? ü༏ SOLVING THIS IS COMPLETELY OPTIONAL. DESIGNED TO PROVIDE BETTER UNDERSTANDING. WILL NOT COUNT FOR HW GRADES. PRACTICE PROBLEM 2 Heather is dlying from city A to city C with a connection in city B. The probability her dirst dlight arrives on time is 0.25. If the dlight is on time, the probability that her luggage will make the connecting dlight is 0.85, but if the dlight is delayed, the probability that the luggage will make it is only 0.65. In either case, Heather makes the dlight. (a) What is the probability that her luggage is
there to meet her in city C? (b) If Heather’s luggage is not there to meet her, what is the probability that Heather was late in arriving in city B? [THIS WILL BE A HW 2 PROBLEM] PRACTICE PROBLEM 3 v༇ Suppose a drug test is 99 % sensitive and 99 % specidic. That is , the test will produce 99% true positive results for drug us...
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 Fall '07
 Lv
 Probability, Probability theory

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