WeightedGrader

Weighted Graders

Standard Problem Grader: give full credit if all answers are correct and zero credit if some answers are incorrect.

Problem Techniques Index

PG problem file

Explanation

loadMacros("PGanswermacros.pl"); # usual initialization, setup, and main text go here # Answer evaluation install_problem_grader(~~&std_problem_grader); $showPartialCorrectAnswers = 0; ANS($a->cmp()); ANS($b->cmp()); ANS($c->cmp());

Answer Evaluation: Be sure to load PGanswermacros.pl or PGstandard.pl (which loads PGanswermacros.pl). We use install_problem_grader(~~&std_problem_grader); to give full credit only if all answers are correct, and zero credit otherwise. We should probably also hide feedback on whether answers are partially correct or not by setting $showPartialCorrectAnswers=0;. The standard problem grader is recommended for true / false and multiple choice questions to prevent students from guessing and receiving either feedback or partial credit that tells them whether their guess was correct.

Weighted Grader: assign different weights (percentages) to each answer in a problem.

PG problem file	Explanation
DOCUMENT(); loadMacros( "PGstandard.pl", "PGcourse.pl", "MathObjects.pl", "weightedGrader.pl", ); install_weighted_grader(); TEXT(beginproblem);	Initialization: We need to include the weightedGrader.pl macro file and immediately install it using install_weighted_grader();.
Context("Numeric"); Context()->variables->add(t=>"Real"); Context()->strings->add(A=>{},B=>{}); $r = random(2,4,1); $answer1 = Real("pi * $r**2"); $answer2 = Formula("($r - 1) * x**2 * t") -> reduce; $answer3 = String("A");	Set-up: To show how this works with MathObjects, we add some variables and strings to the context.
Context()->texStrings; BEGIN_TEXT Enter \( \pi $r^2 \): \{ans_rule(10)\} Enter \( $answer2 \): \{ans_rule(10)\} Enter A: \{ans_rule(10)\} END_TEXT Context()->normalStrings;	Main Text: Answer boxes are as usual.
$showPartialCorrectAnswers = 0; WEIGHTED_ANS( ($answer1)->cmp(), 40 ); WEIGHTED_ANS( ($answer2)->cmp(), 40 ); WEIGHTED_ANS( ($answer3)->cmp(), 20 ); ENDDOCUMENT();	Answer Evaluation: Use WEIGHTED_ANS( evaluator, weight ); instead of ANS( evaluator );. The code given assigns 40% to each of the first two answers, and 20% to the last answer. The weights should be positive integers that sum to 100.

Problem Techniques Index