70)Two stores sell a certain MP3 players. Store A has 34% of the sales, 5% of which are of defectiveitems, and store B has 66% of the sales, 1% of which are of defective items. The difference indefective rates is due to different levels of pre-sale checking of the product. A person receivesa defective item of this product as a gift. What is the probability it came from store B?70)A)0.5667B)0.7083C)0.275D)0.22Answer:C

71)The incidence of a certain disease on the island of Tukow is 4%. A new test has been developedto diagnose the disease. Using this test, 91% of those who have the disease test positive while4% of those who do not have the disease test positive (false positive). If a person tests positive,what is the probability that he or she actually has the disease?71)

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72)Quality Motors has three plants. Plant 1 produces 35% of the car output, plant 2 produces 20%and plant 3 produces the remaining 45%. One percent of the output of plant 1 is defective, 1.8%of the output of plant 2 is defective and 2% of the output of plant 3 is defective. The annualtotal production of Quality Motors is 1,000,000 cars. A car chosen at random from the annualoutput and is found defection. What is the probability that it came from plant 2?72)

73)In Cumberland County, 55% of registered voters are Democrats, 30% are Republicans and 15%are independent. During a recent election, 35% of the Democrats voted, 65% of the Republicansvoted, and 75% of the independent voted. What is the probability that someone who voted is aDemocrat?73)

74)In Cumberland County, 55% of registered voters are Democrats, 30% are Republicans and 15%are independent. During a recent election, 35% of the Democrats voted, 65% of the Republicansvoted, and 75% of the independent voted. What is the probability that someone who voted is aRepublican?74)A)0.385B)0.065C)0.39D)0.225Answer:C

75)An water well is to be drilled in the desert where the soil is either rock, clay or sand. Theprobability of rock P(R)=0.53. The clay probability is P(C)=0.21. The sand probability is P(S)=0.26. It if it rock, a geological test gives a positive result with 35% accuracy. If it is clay, thistest gives a positive result with 48% accuracy. The test gives a 75% accuracy for sand. Giventhe test is positive, what is the probability that soil is rock, P(rock | positive)?75)