Practice Test 3_Bus2023_spring09_solutions

Practice Test 3_Bus2023_spring09_solutions - Practice Test...

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Practice Test 3 –Bus 2023 Directions: For each question find the answer that is the best solution provided. There is only one correct answer. 1. A random variable that can assume only a finite number of values is referred to as a(n) a. infinite sequence b. finite sequence c. discrete random variable d. discrete probability function ANSWER: c 2. The number of customers that enter a store during one day is an example of a. a continuous random variable b. a discrete random variable c. either a continuous or a discrete random variable, depending on the number of the customers d. either a continuous or a discrete random variable, depending on the gender of the customers ANSWER: b 3. An experiment consists of measuring the speed of automobiles on a highway by the use of radar equipment. The random variable in this experiment is speed, measured in miles per hour. This random variable is a a. discrete random variable b. continuous random variable c. complex random variable d. None of these alternatives is correct. ANSWER: b 4. A measure of the average value of a random variable is called a(n) a. variance b. standard deviation c. expected value d. None of the alternative answers is correct. ANSWER: c Note: So we can write E(x) = μ 5. The expected value for a binomial probability distribution is a. E( x ) = pn (1 - n ) b. E( x ) = p (1 - p ) c. E( x ) = np d. E( x ) = np (1 - p ) ANSWER: c 1
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6. The variance for the binomial probability distribution is a. Var( x ) = p (1 - p ) b. Var( x ) = np c. Var( x ) = n (1 - p ) d. Var( x ) = np (1 - p ) ANSWER: d 7. Assume that you have a binomial experiment with p = 0.4 and a sample size of 50. The variance of this distribution is a. 20 b. 12 c. 3.46 d. Not enough information is given to answer this question. ANSWER: b Recall that variance of the binomial is Var( x ) = np (1 - p ) = 50(0.4)(0.6) = 12 8. Twenty percent of the students in a class of 100 are planning to go to graduate school. The standard deviation of this binomial distribution is a. 20 b. 16 c. 4 d. 2 ANSWER: c Recall that variance of the binomial is Var( x ) = np (1 - p ) = 100(0.2)(0.8) = 16 Std(x) = = 4 Exhibit 5-8 The student body of a large university consists of 60% female students. A random sample of 8 students is selected. 9. Refer to Exhibit 5-8. What is the random variable in this experiment? a. the 60% of female students b. the random sample of 8 students c. the number of female students out of 8 d. the student body size ANSWER: c 10. Refer to Exhibit 5-8. What is the probability that among the students in the sample exactly two are female? a. 0.0896 b. 0.2936 c. 0.0413 d. 0.0007 ANSWER: c Recall that P( X = x) = ( n x ) p x (1-p) (n-x) P( X = 2) = ( 8 2 ) )0.6 2 (0.4) (8-2) = 0.0413 2
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11. Refer to Exhibit 5-8. What is the probability that among the students in the sample at least 7 are female? a.
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This note was uploaded on 03/27/2010 for the course FINANCE Ali taught by Professor Finance during the Spring '10 term at Abraham Baldwin Agricultural College.

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Practice Test 3_Bus2023_spring09_solutions - Practice Test...

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