## DESCRIPTION ## Statistics: Probability ## ENDDESCRIPTION ## KEYWORDS('statistics', 'probability') ## naw tagged this problem. ## DBchapter('Continuous Probability Distributions') ## DBsection() ## Date('6/28/2005') ## Author('Nolan A. Wages') ## Institution('UVA') ## TitleText1('Statistics for Management and Economics') ## EditionText1('6') ## AuthorText1('Keller, Warrack') ## Section1() ## Problem1() DOCUMENT(); # This should be the first executable line in the problem. loadMacros( "PG.pl", "PGbasicmacros.pl", "PGchoicemacros.pl", "PGanswermacros.pl", "PGnumericalmacros.pl", "PGstatisticsmacros.pl", "PGauxiliaryFunctions.pl" ); TEXT(beginproblem()); \$showPartialCorrectAnswers = 1; ## install_problem_grader(~~&std_problem_grader); \$z = 4; while (\$z > 3) { \$a = random(60000,70000,10000); \$b = \$a+random(10000,15000,1000); \$c = random(3000,7000,1000); \$d = \$b+random(3000,10000,1000); \$z = (\$b-\$a)/\$c; } BEGIN_TEXT \$PAR The top-selling Red and Voss tire is rated \$a miles, which means nothing. In fact, the distance the tires can run until wear-out is a normally distributed random variable with a mean of \$b miles and a standard deviation of \$c miles. \$PAR A. What is the probability that the tire wears out before \$a miles? \$PAR Probability = \{ans_rule(15)\} \$PAR B. What is the probability that a tire lasts more than \$d miles? \$PAR Probability = \{ans_rule(15)\} \$PAR END_TEXT \$ans1 = normal_prob('-infty', \$a, mean=>\$b, deviation=>\$c); \$ans2 = normal_prob(\$d, 'infty', mean=>\$b, deviation=>\$c); ANS(num_cmp(\$ans1)); ANS(num_cmp(\$ans2)); ENDDOCUMENT(); # This should be the last executable line in the problem.