Stat 225 Practice Exam 2 Solutions

# Stat 225 Practice Exam 2 Solutions - STAT 225 Review Exam 2...

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1. For a certain board game, the moves are made by a spinner. The spinner is equally likely to land in any of ten places. The number on the place where you land indicates the number of spots you must move on the board. Two of the places have a “-1”, in which you must move one spot back on the board. Four of the places have a “0”, three have a “1” and one has a “2”. Let X be the number of spots you must move after one spin. a) Fill in the numbers in the PMF below. (4 pt) x -1 0 1 2 p(x) 0.2 0.4 0.3 0.1 b) Find the probability that you do not move backward. (3 pts) (0 ) 1 ( 1 ) 1 0 . 2 0 . 8 PX ≥= = = = c) Find the expected value and variance of X. (6 pts) ( ) ( 1)*0.2 0*0.4 1*0.3 2*0.1 0.3 EX = −++ += 22 2 2 2 ( ) ( 1) *0.2 0 *0.4 1 *0.3 2 *0.1 0.9
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## This note was uploaded on 04/30/2008 for the course MA 225 taught by Professor Asian during the Spring '08 term at Purdue.

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Stat 225 Practice Exam 2 Solutions - STAT 225 Review Exam 2...

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