Development:Question engine - Revision history

Peter2108: /* How the penalty is determined */

2008-03-30T19:55:12Z

How the penalty is determined

← Older revision		Revision as of 19:55, 30 March 2008
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	Each question has a 'penalty' field (which should really be called 'penaltyfactor') which is a number between 0 and 1. The penalty for a wrong response is calculated as the product ($quiz->penalty * $quiz->grade), i.e., as the product of the penaltyfactor with the maximum achievable grade for the question. This product is stored in $state->penalty. So $quiz->penalty is the fraction of the maximum grade that is subtracted as a penalty for each wrong response.		Each question has a 'penalty' field (which should really be called 'penaltyfactor') which is a number between 0 and 1. The penalty for a wrong response is calculated as the product ($quiz->penalty * $quiz->grade), i.e., as the product of the penaltyfactor with the maximum achievable grade for the question. This product is stored in $state->penalty. So $quiz->penalty is the fraction of the maximum grade that is subtracted as a penalty for each wrong response.

	The $quiz->penalty field has a default value of 0.1, both in the database and in mod/quiz/defaults.php. This default can of course be overwritten by the admin on the quiz configuration page. This admin-selected default is (as usual for admin defaults) stored in $CFG->quiz_penalty. The teacher can choose a different penalty factor for each individual question when adding or editing a question.		The $quiz->penalty field has a default value of 0.1, both in the database and in mod/quiz/defaults.php. This default can of course be overwritten by the admin on the quiz configuration page. This admin-selected default is (as usual for admin defaults) stored in $CFG->quiz_penalty. The teacher can choose a different penalty factor for each individual question when adding or editing a question. (In Moodle 1.8 the default value of 0.1 is actually hardcoded at line 87 of moodle/question/type/edit_question_form.php)

	Now if a student makes repeated wrong attempts (or partially correct attempts) the penalties for all these attempts are added up in $state->sumpenalties. The mark for the question is then calculated as the mark for the last graded response minus the sum of the penalties.		Now if a student makes repeated wrong attempts (or partially correct attempts) the penalties for all these attempts are added up in $state->sumpenalties. The mark for the question is then calculated as the mark for the last graded response minus the sum of the penalties.

Tsala: cat edit

2007-06-18T09:21:23Z

cat edit

← Older revision		Revision as of 09:21, 18 June 2007
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	The function quiz_apply_penalty_and_timelimit() subtracts the penalty in $state->sumpenalty from the raw grade in $state->raw_grade to obtain $state->grade for the response. However it is ensured that the grade of a new attempt at the question never falls below the previously achieved grade. This function also increases $state->sumpenalty by the amount in $state->penalty. The assumption is that $state->penalty has just been set appropriately by the code calling this function, e.g., quiz_process_responses.		The function quiz_apply_penalty_and_timelimit() subtracts the penalty in $state->sumpenalty from the raw grade in $state->raw_grade to obtain $state->grade for the response. However it is ensured that the grade of a new attempt at the question never falls below the previously achieved grade. This function also increases $state->sumpenalty by the amount in $state->penalty. The assumption is that $state->penalty has just been set appropriately by the code calling this function, e.g., quiz_process_responses.

	[[Category:Developer]]		[[Category:Developer\|Question engine]]
	[[Category:Quiz]]		[[Category:Quiz]]

Fulano2040: /* Sessions, States, Events */

2007-06-13T00:13:58Z

Sessions, States, Events

← Older revision		Revision as of 00:13, 13 June 2007
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	;validate:The student has asked for his responses to be validated. This means it is checked that they are valid responses. In the case of mathematical questions which requires the input of a mathematical expression in some linear format the question type may want to display the validated result back to the student in typeset form. Similar things may apply to other subject-specific question types. If a student response is found to be invalid the student is told so but no penalty is applied. The invalid response is stored with the state.		;validate:The student has asked for his responses to be validated. This means it is checked that they are valid responses. In the case of mathematical questions which requires the input of a mathematical expression in some linear format the question type may want to display the validated result back to the student in typeset form. Similar things may apply to other subject-specific question types. If a student response is found to be invalid the student is told so but no penalty is applied. The invalid response is stored with the state.
	;grade:The student has pressed the submit button. The grade is calculated and stored with the attempt.		;grade:The student has pressed the submit button. The grade is calculated and stored with the attempt.
	;duplicategrade:The student has pressed the submit button but the response to this question has not actually changed. This happens a lot in quizzes with several questions on on page where the student may have changed the responses for one question only. I believe that states created by this type of event are not stored in the database.		;duplicategrade:The student has pressed the submit button but the response to this question has not actually changed. This happens a lot in quizzes with several questions on one page where the student may have changed the responses for one question only. I believe that states created by this type of event are not stored in the database.
	;close:The last state in a session which is now closed. Currently a session closes only when the attempt closes, either because the student requests it or because the timelimit elapses.		;close:The last state in a session which is now closed. Currently a session closes only when the attempt closes, either because the student requests it or because the timelimit elapses.

Fulano2040: /* Sessions, States, Events */

2007-06-13T00:03:22Z

Sessions, States, Events

← Older revision		Revision as of 00:03, 13 June 2007
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	When a new attempt is started, a new '''session''' is started for each question. So in a sense a session is for a question what an attempt is for a whole quiz. A question session lasts no longer than an attempt and for each question there can only by one session within one attempt.		When a new attempt is started, a new '''session''' is started for each question. So in a sense a session is for a question what an attempt is for a whole quiz. A question session lasts no longer than an attempt and for each question there can only by one session within one attempt.

	Moodle allows the student to interact with a question repeatedly within one session and each such interaction leads to a new '''state'''. The first state is created when the session is created. A new state is then created when a student saves ~~and answer or~~ validates ~~an answer~~ or submits an answer or .... The student's responses and, if appropriate, the results of response processing (grading) are stored in the new state that gets created.		Moodle allows the student to interact with a question repeatedly within one session and each such interaction leads to a new '''state'''. The first state is created when the session is created. A new state is then created when a student saves, validates or submits an answer or .... The student's responses and, if appropriate, the results of response processing (grading) are stored in the new state that gets created.

	The type of '''event''' that led to the creation of a particular state is saved along with the state. The types of events currently used are:		The type of '''event''' that led to the creation of a particular state is saved along with the state. The types of events currently used are:

TimHunt: /* Code documentation */

2007-03-20T09:21:27Z

Code documentation

← Older revision		Revision as of 09:21, 20 March 2007
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	==Code documentation==		==Code documentation==

	The code is documented according to phpdoc conventions. The explanations here in the wiki are meant to complement this.		The code is documented according to [http://www.phpdoc.org/ PHPdocumentor] conventions. The explanations here in the wiki are meant to complement this.

	Inline comments should be used liberally in the code. The following conventions make it easier to search for comments with special meaning:		Inline comments should be used liberally in the code. The following conventions make it easier to search for comments with special meaning:
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	** Subpackage questiontypes - code that relates to the question types, including the question type base class.		** Subpackage questiontypes - code that relates to the question types, including the question type base class.
	** Subpackage importexport - code that relates to importing and exporting questions.		** Subpackage importexport - code that relates to importing and exporting questions.

			Generally, the base classes default_questiontype and qformat_default should contain most of the documentation, since all question types should follow the same interface. There is no value in repeating the same information on all the various subclasses. The subclasses should concentrate on describing any new methods they have that do not come from the base class.

			See the [http://manual.phpdoc.org/HTMLSmartyConverter/HandS/phpDocumentor/tutorial_phpDocumentor.quickstart.pkg.html#coding.phpcomments PHPdocumentor manual] for more advice on writing good comments.

	Moodle PHPdocs can be seen here: http://phpdocs.moodle.org/.		Moodle PHPdocs can be seen here: http://phpdocs.moodle.org/.

TimHunt: /* Code documentation */

2007-03-19T17:09:49Z

Code documentation

← Older revision		Revision as of 17:09, 19 March 2007
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	** Subpackage importexport - code that relates to importing and exporting questions.		** Subpackage importexport - code that relates to importing and exporting questions.

	Moodle PHPdocs can be seen here: [http://phpdocs.moodle.org/].		Moodle PHPdocs can be seen here: http://phpdocs.moodle.org/.

	==API==		==API==

TimHunt: /* Code documentation */

2007-03-19T17:09:40Z

Code documentation

← Older revision		Revision as of 17:09, 19 March 2007
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	** Subpackage questiontypes - code that relates to the question types, including the question type base class.		** Subpackage questiontypes - code that relates to the question types, including the question type base class.
	** Subpackage importexport - code that relates to importing and exporting questions.		** Subpackage importexport - code that relates to importing and exporting questions.

			Moodle PHPdocs can be seen here: [http://phpdocs.moodle.org/].

	==API==		==API==

TimHunt: /* Code documentation */

2007-03-19T17:08:51Z

Code documentation

← Older revision		Revision as of 17:08, 19 March 2007
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	* use TODO in comments about things that need to be done		* use TODO in comments about things that need to be done
	* use ??? in comments that are questions about the code		* use ??? in comments that are questions about the code

			Code is organised into packages
			* Package questionbank - code that relates to the questionbank system
			** Subpackage questiontypes - code that relates to the question types, including the question type base class.
			** Subpackage importexport - code that relates to importing and exporting questions.

	==API==		==API==

Ppichet: /* Question types */

2007-03-14T19:55:23Z

Question types

← Older revision		Revision as of 19:55, 14 March 2007
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	*Question options object		*Question options object
	*State options object		*State options object
			[[Development:Question type code flow]]

	It is hoped that Moodlers will contribute a lot of non-core question types in the future. For this it would be good to start a [[How to write a question type plugin]].		It is hoped that Moodlers will contribute a lot of non-core question types in the future. For this it would be good to start a [[How to write a question type plugin]].

Tsala: Question engine moved to Development:Question engine

2007-01-09T11:03:59Z

Question engine moved to Development:Question engine

← Older revision	Revision as of 11:03, 9 January 2007
(No difference)