Midterm_2011_Winter_version2_soln

# Midterm_2011_Winter_version2_soln - ECON 2500M:...

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1 ECON 2500M: Introductory Statistics for Economists Midterm Version 2 - Solutions I. ( 20 points) Multiple choice questions, NO explanation needed . 1. Using the standard normal distribution tables, what is the area under the standard normal curve corresponding to –0.5 < Z < 1.2? A) 0.3085 B) 0.8849 C) 0.5764 D) 0.2815 Answer: C 2. The scores on a university examination are normally distributed with a mean of 62 and a standard deviation of 11. If the bottom 10% of students will fail the course, what is the lowest mark that a student can have and still be awarded a passing grade? A) 62 B) 57 C) 48 D) 40 Answer: C 3. When possible, what is the best way to establish that an observed association is the result of a cause-and-effect relation? A) Collect larger data set. B) Obtain the correlation coefficient. C) Use a well-designed experiment. D) Examine z -scores rather than the original variables. Answer: C 4. In order to assess the effects of exercise on reducing cholesterol, a researcher sampled 50 people from a local gym who exercise regularly and 50 people from the surrounding community who do not exercise regularly. Each subject reported to a clinic to have their cholesterol measured. The subjects were unaware of the purpose of the study, and the technician measuring the cholesterol was not aware of whether the subject exercises regularly or not. What type of study is this? A) An observational study. B) An experiment, but not a double-blind experiment. C) A double-blind experiment. D) A matched-pairs experiment. Answer: A

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2 5. Twelve people, who suffer from chronic fatigue syndrome, volunteer to take part in an experiment to see if shark fin extract will increase one’s energy level. Eight of the volunteers are men and four are women. Half of the volunteers are to be given shark fin extract twice a day and the other half a placebo twice a day.
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## This note was uploaded on 08/28/2011 for the course ECON 2500 taught by Professor Xianghongli during the Winter '11 term at York University.

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Midterm_2011_Winter_version2_soln - ECON 2500M:...

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