Unformatted text preview: 3. What is standard deviation of the number she is expected to get right? n = 100 p = .25 standard deviation = (100*.25(1.25))^(1/2) = 4.33 4. What is the chance that Pat gets more than 35 correct? Want: P(X>35) = 1 P(z<2.31) = 1  .9896 = .0104 Mean = 100*.25 = 25 z = (35 – 25)/4.33 = 2.31 Suppose a gas station claims that 25% of all cars are low on oil. The station owner takes a random sample of 7 cars and checks their oil levels. She counts the number of cars in the sample that are low on oil. 5. What is the expected number of cars with low oil from this sample? mean = 7*.25 = 1.75 cars 6. What is the probability that at least 1 of the cars is low on oil? Want: P(X>=1) = 1 – P(X=0) = 1 – .1335 = .8665 1...
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 Fall '07
 rumseyjohnson
 Standard Deviation, Probability theory, Cauchy distribution

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