Stat104_more_midterm_practice_sol

# Stat104_more_midterm_practice_sol - Multiple Choice(3...

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Multiple Choice (3 points each) 1) The median waiting time for patients to see a doctor at a local emergency room is much smaller than the mean waiting time. Which of the following is most consistent with this information (circle one): a. A histogram of the waiting times would be symmetric. b. A histogram of the waiting times would be left-skewed. c. A histogram of the waiting times would be right-skewed. 2) A student is studying very hard in a fluid dynamics course, but he knows he will either pass or not pass. Suppose this student, Jack Daniels, has a probability of 0.90 for studying the night before the exam. Also, he has a probability of 0.75 for passing the exam. If the probability of passing the exam, given that he studied the night before, is 0.82, what may you conclude? a. The probability of Jack not passing the exam is 0.10. b. P(Jack studies OR Jack passes) is greater than 0.75. c. P(Jack does not pass AND Jack studies) is greater than 0.5. d. P(Jack passes AND Jack studies) is greater than 0.75. e. None of the above 3) If Steve and Doug Butabi want to find the proportion of people who believe they can move their heads graciously, how large of a sample size is required so that the margin of error is at most 2 percentage points with a 95% confidence level? a. 3382 b. 4148 c. 34 d. 266 e. None of the above 4) In the Land of Chocolate, three friends (Hershey, Nougat, and B.C.) all have to make tough decisions about the next phase of their life where they have ONLY two options: going to college or working in the nearby sugar mines of Dos Catorce. Suppose the following probabilities are true: P (Hershey goes to college) = 0.2 = P (Nougat works at the sugar mines), P (B.C. goes to college) = 0.7. If each of them makes their choice independent of the others, what is the probability of Hershey and Nougat going to college while B.C. works at the sugar mines? a. 0.112 b. 0.048 c. 0.028 d. None of the above

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5) The following diagram comes from a famous piece of music. A random sample of 81 people indicated that 19 people knew the piece of music from the diagram alone. A random sample of 200 people (independent from the first) indicated that 175 people knew the piece of music when it was played on a piano. Construct a 95% confidence interval for the population proportion of people who know the piece of music from the diagram alone. a)
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## This note was uploaded on 03/27/2012 for the course STATS 104 taught by Professor Michaelparzen during the Fall '11 term at Harvard.

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Stat104_more_midterm_practice_sol - Multiple Choice(3...

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