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# Annotation of /trunk/NationalProblemLibrary/UVA-Stat/setStat212-Homework04/stat212-HW04-20.pg

 1 : jjholt 451 ## DESCRIPTION 2 : ## Statistics: Probability 3 : ## ENDDESCRIPTION 4 : 5 : ## KEYWORDS('statistics', 'probability') 6 : ## naw tagged this problem. 7 : 8 : ## DBchapter('Probability') 9 : ## DBsection() 10 : ## Date('6/14/2005') 11 : ## Author('Nolan A. Wages') 12 : ## Institution('UVA') 13 : ## TitleText1('Statistics for Management and Economics') 14 : ## EditionText1('6') 15 : ## AuthorText1('Keller, Warrack') 16 : ## Section1() 17 : ## Problem1() 18 : 19 : 20 : DOCUMENT(); # This should be the first executable line in the problem. 21 : 22 : loadMacros( 23 : "PG.pl", 24 : "PGbasicmacros.pl", 25 : "PGchoicemacros.pl", 26 : "PGanswermacros.pl", 27 : "PGnumericalmacros.pl", 28 : "PGstatisticsmacros.pl", 29 : "PGauxiliaryFunctions.pl" 30 : ); 31 : 32 : TEXT(beginproblem()); 33 : $showPartialCorrectAnswers = 1; 34 : ## install_problem_grader(~~&std_problem_grader); 35 : 36 :$a1 = random(.20,.25,.01); 37 : $a2 = random(.10,.15,.01); 38 :$a3 = random(.50,.60,.01); 39 : $a4 = 1-($a1+$a2+$a3); 40 : 41 : BEGIN_TEXT 42 : $PAR 43 : The owner of an appliance store is interested in the 44 : relationship between the price at which an item is 45 : sold (regular or sale price) and the customer's decision 46 : on whether to purchase and extended warranty. After 47 : analyzing her records, she produced the following joint 48 : probabilities: 49 : 50 : $51 : \begin{array}{c|c|c} 52 : & \mbox{Purchased} & \mbox{Did not purchase} \\ 53 : & \mbox{extended warranty} & \mbox{extended warranty} \\ \hline 54 : \mbox{Regular Price} & a1 & a3 \\ \hline 55 : \mbox{Sale Price} & a2 & a4 \\ 56 : \end{array} 57 :$ 58 : 59 : 60 :$PAR 61 : A. What is the probability that a customer who 62 : bought an item at the regular price purchased the 63 : extended warranty? 64 : $PAR 65 : Probability = \{ans_rule(15)\} 66 :$PAR 67 : B. What is the probability that a customer buys an extended warranty? 68 : $PAR 69 : Probability = \{ans_rule(15)\} 70 : 71 :$PAR 72 : 73 : END_TEXT 74 : 75 : ANS(num_cmp($a1/($a1+$a3))); 76 : ANS(num_cmp($a1+\$a2)); 77 : 78 : 79 : ENDDOCUMENT(); # This should be the last executable line in the problem.