MultipleSelectProblems

Multiple Select Problems (or Checkbox Multiple Choice or Select All That Apply): PG Code Snippet

This code snippet shows the essential PG code to include multiple select question (or checkbox multiple choice or select all that apply) in a problem. A multiple choice question has only one correct answer, whereas a checkbox multiple choice question may require several items to be selected at the same time to be correct. Note that these are insertions, not a complete PG file. This code will have to be incorporated into the problem file on which you are working.

Note that in this example we use old-style checkbox multiple choice answer objects. The new-style MathObjects do not yet have a checkbox multiple choice answer object yet.

Problem Techniques Index

PG problem file	Explanation
DOCUMENT(); loadMacros( "PG.pl", "PGbasicmacros.pl", "PGchoicemacros.pl", "PGanswermacros.pl" ); # Do not show which answers are incorrect. $showPartialCorrectAnswers = 0;	In the initialization section of the file we need to include PGchoicemacros.pl and PGanswermacros.pl in our list of loaded macro files. We should also set $showPartialCorrectAnswers = 0; to hide the correct answers from students until they have answered everything correctly.
# Make a new checkbox multiple choice $cmc = new_checkbox_multiple_choice(); # $cmc now "contains" the checkbox multiple choice object. # Insert a question and matching answers in the q/a list $cmc -> qa ( "Please select all vectors that are named.", # question "\(\vec{a} = \langle 1, 1, 1 \rangle \)", # a correct answer "\(\vec{n} = \langle 1, -1, 0 \rangle \)", # another correct answer "\(\vec{z} = \langle 0, 0, 0 \rangle \)", # Use " ... " to enter a string ); # Insert some incorrect answers $cmc -> extra( "\(\langle -2, 2, 2 \rangle\)", "\(\langle \pi, 4, -1 \rangle\)", ); $cmc->makeLast("None of the above"); # Note that unlike match lists and select lists, you cannot call qa() again	In the problem set-up, we create a new checkbox multiple choice object with new_checkbox_multiple_choice, and then store the question and correct answer with the qa method. Other answers are specified as a list of arguments to the extra method. To force an answer (either a new extra answer, or the correct answer) to appear last in the list of options, use the makeLast method. All other answers will be scrambled when the multiple choice problem is shown to students.
TEXT(beginproblem()); # Print the text using $cmc->print_q() for the questions and # $cmc->print_a() to print the answers. BEGIN_TEXT This is the place to insert additional text if you wish. $PAR \{ $cmc -> print_q() \} $PAR \{ $cmc -> print_a() \} END_TEXT	In the text section we print the question and answers.
# Enter the correct answers to be checked against the answers to the students. ANS(checkbox_cmp( $cmc->correct_ans ) ) ; ENDDOCUMENT();	And we grade the problem with checkbox_cmp.

Problem Techniques Index