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Unformatted text preview: Stat 3011 Sample Final Exam Sample Final Exam 1. Insert the words ‘point’ and ‘interval’ into the appropriate blanks: A(n) interval estimate reflects the potential error in calculating a(n) point estimate for an unknown population parameter. 2. Do students tend to improve their SAT Mathematics score the second time they take the test? A random sample of 10 students who took the test twice received the following scores: Student 1 2 3 4 5 6 7 8 9 10 First score 450 520 720 600 400 530 600 580 550 520 Second score 460 550 700 630 420 520 630 570 560 580 What is the most appropriate way to answer this question and analyze this data? (a) Conduct a matched pairs test for means. (b) Conduct a two-sample test for means. (c) Calculate the difference between the average score on the 1st test and the average score on the 2nd test. 3. Researchers studying marital happiness classify marriages into three categories: not happy, fairly happy, or very happy. In investigating marriages they also collect data on the education levels and incomes of their subjects. The incomes are classified as below average, average, or above average. Draw 2 separate lines connecting the most appropriate test to perform for the following two research questions: Test Research Question one-sample test 1. The divorce rate in America is nearing 50%. for a proportion Are more than half of all marriages unhappy ones? two-sample test 2. Are couples with college educations more likely for proportions to have ‘very happy’ marriages than couples with no college education? Answer: 1 = one-sample test and 2 = two-sample test 1/12 Stat 3011 Sample Final Exam 4. The distribution of household use of electricity has a normal distribution with a mean of 673 kilowatt-hours and a standard deviation of 556 kilowatt-hours. 99.98% of all households use less than what amount of electricity? .9998 corresponds to a z-score of 3.49 unstandardize: Let x be the 99.98th percentile of the distribution of electricity use. x = μ + σz = 673 + 556(3 . 49) = 2613 . 44 Problem 5 The Wonderlic is a 50 question IQ test invented by E. F. Wonderlic in the 1930s when he was a psychology graduate student at Northwestern University. A score of 20 correct is meant to correspond to an IQ of 100 while a score of 10 indicates literacy. About 2.5 million people take this test every year but it is perhaps best known for its use at the NFL draft combine. In the past, the Wonderlic scores of NFL draft participants have been (roughly) normally distributed with an average of 21 points and a standard deviation of 6 points. (a) If we randomly select a past participant in the NFL draft, what is the probability that this person scored above 25 points?...
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This note was uploaded on 10/02/2011 for the course STAT 3011 taught by Professor Wang,zhan during the Spring '09 term at Minnesota.
- Spring '09