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Unformatted text preview: FINAL EXAM STAT 101, Instructors: A. Rakhlin December 21, 2010 Student Name: Section: Instructions Use the space provided to answer questions. You can use the back of these pages as scratch paper. You must show work and give explanations (except for the multiple-choice questions). Rules of uniformity: Two-sided letter crib sheet, calculator ok (even with statistical functions and graphing), otherwise closed notes, closed book. No cell phones visible! Rules of Fairness: Complete this exam entirely on your own. Do not acquire information from other stu- dents or the outside in any form. Do not take copies of this exam out of this room. You have two hours for this exam. Any student observed continuing to write after time has been called will be documented and points will be deducted. Rules of Consideration: Be considerate to others by not causing commotion and distraction. If you finish early, leave quietly; avoid slamming doors. Honor code applies to the above Rules. Your signature: About this test: When more than one choice seems reasonable, pick the one that is best. STOP WAIT UNTIL YOU ARE INSTRUCTED TO PROCEED. 21 questions for a total of 100 points. STAT 101 Final Exam 1. (2 points) How is the standard deviation in a sample affected by the removal of three most extreme observations on both sides? (a) It remains the same. (b) It becomes smaller. (c) It becomes larger. (d) There is an effect but it is not predictable. 2. (2 points) For a random variable X with a normal distribution, P ( X > ) = (a) 0 (b) 1 (c) 1/2 (d) None of the above 3. (3 points) If the random variables X and Y have zero correlation, then they are (a) always independent (b) always disjoint (c) always linearly associated (d) None of the above 4. (3 points) If the probability of a market drop greater than 3% is 0.005 and the probability of a market drop greater than 5% is 0.001, then the probability of a market drop between 3% and 5% is (a) 0.004 (b) 2% (c) not known because we dont know the probability of overlap of the events (d) None of the above 5. (3 points) While manipulating data from a survey of households, 50% of the cases got corrupted and were lost. As a consequence, by approximately how much will the standard error SE of the mean grow? (a) about 40% (b) about 50% (c) about 100% (d) about 200% 6. (2 points) (True/False) If X and Y are two random variables with SD ( X ) = SD ( Y ), then X and Y are identically distributed....
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This note was uploaded on 04/04/2012 for the course STAT 101 taught by Professor Heller during the Fall '08 term at UPenn.
- Fall '08