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SampleExam1Sol - Stat3011 Sample Midterm 1 Sample Midterm 1...

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Stat3011 Sample Midterm 1 Sample Midterm 1 Section 1: Multiple Choice, Miscellaneous, and Short Answer 1. Which of the following is NOT a measure of the spread of a data set? (a) range (b) median (c) standard deviation (d) variance 2. Which of the following is least affected if an extreme outlier is added to your data? (a) median (b) mean (c) standard deviation 3. What percent of the observations in a distribution lie between the first quartile and maximum? (a) 25% (b) 50% (c) 75% 4. Sue is taking an English class and a History class. Assume the probability that she gets an A in English is .3, the probability she gets an A in History is 0.4, and the probability she gets an A in both is 0.15. What is the probability she gets an A in English or History (or both)? Let E be the event of an A in English and H be the event of an A in History. Then P ( E H ) = P ( E ) + P ( H ) - P ( E H ) = . 3 + . 4 - . 15 = . 55 1/9
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Stat3011 Sample Midterm 1 5. Which of the following is NOT a proper probability? (a) 1.25 It can’t be a probability since it is bigger than 1! (b) 1 (c) 25/100 (d) 0 6. For a distribution that is skewed to the left, (a) the mean is less than the median. (b) the mean is equal to the median. (c) the mean is greater than the median. 7. The scale of scores on an IQ test is approximately Normal with mean 100 and standard deviation 15. The MENSA organization requires its members to have an IQ score of 130 or higher. Approximately what proportion of adults would qualify for membership? z = (130 - 100) / 15 = 2 P ( X > 130) = P ( Z > 2) = P ( Z < - 2) = 0 . 0228 (Using Table A-1) 8. What types of variables are these? Draw lines to connect each example to the appro- priate variable type. Examples: Variable Type: speed of a car continuous, quantitative (speed of a car) credit card number discrete, quantitative (number of accidents) number of accidents at a factory categorical (credit card number) 9. It is important to explore data using both graphical and numerical summaries. When numerically summarizing a data set, we obtain measures of two qualities of the data distributions. What are these two qualities? center and spread 2/9
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Stat3011 Sample Midterm 1 Section 2: Completely answer each question. Show all work for full credit! Problem 1 The 2004 General Social Survey gathered information to assess a possible association between political party affiliation and gender. The results are summarized in the following table: Democrat Independent Republican Total Male 386 475 399 1260 Female 573 516 422 1511 Total 959 991 821 2771 (a) What is the conditional probability that a person is a Democrat given they are a female? P
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SampleExam1Sol - Stat3011 Sample Midterm 1 Sample Midterm 1...

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