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Consolidated tags.


    1 ##DESCRIPTION
3 ##
4 ## CMMK tagged this problem
5
6 ## DBchapter('Inference About a Population')
7 ## DBsection()
8 ## Date('07/12/2005')
9 ## Author('Cristina Murray-Krezan')
10 ## Institution('UVa')
11 ## TitleText1('Statistics for Management and Economics')
12 ## EditionText1('6')
13 ## AuthorText1('Keller, Warrack')
14 ## Section1()
15 ## Problem1()
16
17
18 ##ENDDESCRIPTION
19
20 DOCUMENT();        # This should be the first executable line in the problem.
21
23 "PG.pl",
24 "PGbasicmacros.pl",
25 "PGchoicemacros.pl",
27 "PGgraphmacros.pl",
28 "PGnumericalmacros.pl",
29 "PGstatisticsmacros.pl",
31 );
32
33 TEXT(beginproblem());
34 $showPartialCorrectAnswers = 1; 35 # install_problem_grader(~~&std_problem_grader); 36 37$n1 = random(35,51,2);
38 $n2 = random(36,52,2); 39$xbar1 = random(50,60,0.1);
40 $xbar2 = random(70,80,0.1); 41$s1 = random(5,6,0.1);
42 $s2 = random(10,11,0.1); 43 44$df = $n1 +$n2 - 2;
45 $sp2 = (($n1-1)*$s1**2 + ($n2-1)*$s2**2)/$df;
46
47 $siglev = random(92,98,.5); 48$alpha = 0.01*(100-$siglev); 49 50$tcrit = tdistr($df,$alpha/2);
51 $ucl = ($xbar1 - $xbar2) +$tcrit*sqrt($sp2*(1/$n1 + 1/$n2)); 52$lcl = ($xbar1 -$xbar2) - $tcrit*sqrt($sp2*(1/$n1 + 1/$n2));
53
54
55 BEGIN_TEXT
56 $PAR 57 Two random samples are selected from two independent populations. 58 A summary of the samples sizes, sample means, and sample standard 59 deviations is given below: 60$PAR
61 $62 \begin{array}{lll} 63 n_1 = n1, & \bar{x}_1 = xbar1, & s_1 = s1 \\ 64 n_2 = n2, & \bar{x}_2 = xbar2, & s_2 = s2 \\ 65 \end{array} 66$
67 $PAR 68 Find a$siglev$PERCENT confidence interval for the difference 69 $$\mu_1 - \mu_2$$ of the means, assuming equal population 70 variances. 71$PAR
72
73 Confidence Interval = \{ ans_rule(25) \}
74 $PAR 75 76 END_TEXT 77 78 ANS(interval_cmp("($lcl,\$ucl)", sloppy=>'yes'));
79
80 ENDDOCUMENT();       # This should be the last executable line in the problem.