ec41s10FIN_sol (1)

ec41s10FIN_sol (1) - Kata Bognar kbognar@ucla.edu Economics...

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Unformatted text preview: Kata Bognar kbognar@ucla.edu Economics 41 Statistics for Economists UCLA Spring 2010 Final Exam- answer key - Part I - Multiple Choice Questions (3 points each) 1. A statistician wants to determine the total annual medical costs incurred by all U.S. states from 1981 to 2001 as a result of health problems related to smoking. She polls each of the fifty states annually to obtain health care expenditures, in dollars, on smoking-related illnesses. Which one of the following is NOT a true statement? C (a) The population is all U.S. states. (b) The sample is the same as the population. (c) The data collected are qualitative data. (d) You can consider each state as an element of the study. 2. A research team conducts an experiment on an automotive plant to determine the effect of pro- duction demands on stress levels. Which one of the following describes the drawing of a random sample of all paid employees of the plant? A (a) The team selects names at random from the payroll for the sample. (b) The team selects for the sample the first 20 employees who enter the building after 8:00AM. (c) The team selects for the sample all machine operators. (d) The team puts the names of all employees with more than 6 months experience at their present job into a hat and draws 20 names at random from the hat for the sample. 3. The value that occurs with a maximum frequency in a data set is the: C (a) mean (b) standard deviation (c) mode (d) median Explanation : See the definition of mode in the book. 4. Suppose that there are 10 songs on a CD and you like 6 of them. When you choose shuffle on the CD player each of the 10 songs is played once in a random order. The probability that you like both of the first two songs played is A (a) 1/3 (b) 1/2 (c) 0.36 (d) none of the above Explanation: There are ( 10 2 ) = 45 ways in which any first two songs can be selected and there are ( 6 2 )( 4 ) = 15 ways in which first two songs that you like can be selected. The probability is the ratio of these two: 15 / 45 = 1 / 3 . 5. Which of the following is true? B (a) 5 i =1 i = 10 (b) 5 C 2 = 10 (c) 5 P 2 = 10 1 (d) 5! = 10 Explanation: 5 i =1 i = 1 + 2 + 3 + 4 + 5 = 15 5 C 2 = 5 4 2 = 10 5 P 2 = 5 4 = 20 5! = 5 4 3 2 1 = 120 . 6. A random variable X that takes on four different values has the following distribution: P ( X =- 1) = a, P ( X = 0) = b, P ( X = 1) = 0 . 4 and P ( X = 2) = 0 . 1 . The expected value of X is 0 . 2. The value of the constants a and b are: D (a) a = 0 . 4 and b = 0 . 2 (b) a = 0 . 3 and b = 0 . 2 (c) a = 0 . 2 and b = 0 . 3 (d) none of the above Explanation: E [ X ] = i x i P ( X = x i ) =- 1 a +0 b +1 . 4+2 . 1 = 0 . 2 implies that a = 0 . 4 ....
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This note was uploaded on 12/28/2010 for the course ECON 41 taught by Professor Guggenberger during the Fall '07 term at UCLA.

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ec41s10FIN_sol (1) - Kata Bognar kbognar@ucla.edu Economics...

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