COMM 290 - Final Exam Practice Questions - chapter 3

COMM 290 - Final Exam Practice Questions - chapter 3 - are...

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COMM 290 – Final Exam Review Problems – Chapter 3 Probability Distribution 1. Question 3.4, pg. 89 *No answer* Shown is a probability distribution for the random variable x . x ( ) f x 3 0.25 6 0.50 9 0.25 Total 1.00 a. Compute ( ) E x b. Compute σ2 , variance of x. c. Compute σ , standard deviation of x. 2. Question 3.6, pg. 89 *No answer* According to a survey, 95% of subscribers to the wall street journal interactive edition have a computer at home. For those households, the probability distributions for the number of laptop and desktop computers
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Unformatted text preview: are given (the wall street journal interactive edition subscriber study, 1999) Probability Number of Comps Laptop Desktop 1 2 3 .47 .06 .45 .56 .06 .28 .02 .10 a. What is the expected value of the number of computers per household for each type of computer? b. What is the variance of the number of computers per household for each type of computer? c. Make some comparisons between the number of laptops and the number of desktops owned by the Journals subscribers....
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This note was uploaded on 01/03/2011 for the course COMM 290 taught by Professor Brian during the Winter '09 term at The University of British Columbia.

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