statexam2sum08

statexam2sum08 - Statistics Exam 2 June 4, 2008 By writing...

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Statistics Exam 2 By writing your PID below, you are indicating June 4, 2008 your intention to abide by the honor pledge: PID: This exam contains fifteen short answer questions ( worth 4 points each ) and three long answer questions ( worth 15 points each ) . Please answer in the space provided; if you need more room, indicate clearly that the answer is continued on the back of the page. In all problems where you need to make a calculation, simplify your answer as much as possible. Show your work clearly to be eligible for partial credit. Some PDFs: Some probabilities: f ( x ) = 1 2 !" 2 e # ( X # μ ) 2 " 2 P [ x ! a ] = e " # a f ( x ) = 1 u ! ! P [ X ] = x e ! X ! f ( x ) = ! e " x P [ X ] = N ! X !( N ! X )! p X (1 ! p ) N ! X Short Questions ( 4 points apiece ) 1. X is a random variable with a continuous distribution. Its probability density function is f ( x ) , and its cumulative density function is F ( x ) . What is the relationship between these functions? 2. According to the Center for Disease Control, the average height of a man in the U.S. is 69 inches; the standard deviation is 3 . If this variable has a normal distribution, how would we write its probability density function?

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Econ 400 Midterm 2, page 2 of 8. 3. You collect data from 100 students on the number of hours they spend on the internet in a typical week. The average of this sample is 10 . 2 , with a standard deviation of 4 . 8 . Construct a 95 % confidence interval for the population mean. 4.
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This note was uploaded on 03/19/2010 for the course ECON 400 taught by Professor Turchi during the Spring '08 term at UNC.

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statexam2sum08 - Statistics Exam 2 June 4, 2008 By writing...

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