* @param array $groupstudents students in this group.
* @param int $p number of positions (slots).
* @param float $sumofmarkvariance sum of mark variance, calculated as part of question statistics
- * @return array with two elements:
- * - integer $s Number of attempts included in the stats.
- * - object $quizstats The statistics for overall attempt scores.
+ * @return quiz_statistics_calculated $quizstats The statistics for overall attempt scores.
*/
public function calculate($quizid, $currentgroup, $useallattempts, $groupstudents, $p, $sumofmarkvariance) {
require_once($CFG->dirroot . '/mod/quiz/report/statistics/statistics_form.php');
require_once($CFG->dirroot . '/mod/quiz/report/statistics/statistics_table.php');
require_once($CFG->dirroot . '/mod/quiz/report/statistics/statistics_question_table.php');
-require_once($CFG->dirroot . '/question/engine/statistics.php');
-require_once($CFG->dirroot . '/question/engine/responseanalysis.php');
require_once($CFG->dirroot . '/mod/quiz/report/statistics/statisticslib.php');
/**
* The quiz statistics report provides summary information about each question in
*/
protected $context;
- /** @var object instance of table class used for main questions stats table. */
+ /** @var quiz_statistics_table instance of table class used for main questions stats table. */
protected $table;
/**
if (!$nostudentsingroup) {
// Get the data to be displayed.
- list($quizstats, $questions, $subquestions) =
+ list($quizstats, $questionstats, $subquestionstats) =
$this->get_quiz_and_questions_stats($quiz, $currentgroup, $useallattempts, $groupstudents, $questions);
} else {
// Or create empty stats containers.
$quizstats = new quiz_statistics_calculated($useallattempts);
- $qstats = new question_statistics($questions);
- $questions = $qstats->questions;
- $subquestions = $qstats->subquestions;
+ $questionstats = array();
+ $subquestionstats = array();
}
$quizinfo = $quizstats->get_formatted_quiz_info_data($course, $cm, $quiz);
$this->download_quiz_info_table($quizinfo);
if ($quizstats->s()) {
- $this->output_quiz_structure_analysis_table($quizstats->s(), $questions, $subquestions);
+ $this->output_quiz_structure_analysis_table($quizstats->s(), $questionstats, $subquestionstats);
if ($this->table->is_downloading() == 'xhtml' && $quizstats->s() != 0) {
$this->output_statistics_graph($quiz->id, $currentgroup, $useallattempts);
}
- foreach ($questions as $question) {
+ foreach ($questions as $slot => $question) {
if (question_bank::get_qtype(
$question->qtype, false)->can_analyse_responses()) {
$this->output_individual_question_response_analysis(
- $question, $reporturl, $qubaids);
+ $question, $questionstats[$slot]->s, $reporturl, $qubaids);
- } else if (!empty($question->_stats->subquestions)) {
- $subitemstodisplay = explode(',', $question->_stats->subquestions);
+ } else if (!empty($questionstats[$slot]->subquestions)) {
+ $subitemstodisplay = explode(',', $questionstats[$slot]->subquestions);
foreach ($subitemstodisplay as $subitemid) {
$this->output_individual_question_response_analysis(
- $subquestions[$subitemid], $reporturl, $qubaids);
+ $subquestionstats[$subitemid]->question, $subquestionstats[$subitemid]->s, $reporturl, $qubaids);
}
}
}
print_error('questiondoesnotexist', 'question');
}
- $this->output_individual_question_data($quiz, $questions[$slot]);
- $this->output_individual_question_response_analysis(
- $questions[$slot], $reporturl, $qubaids);
+ $this->output_individual_question_data($quiz, $questionstats[$slot]);
+ $this->output_individual_question_response_analysis($questions[$slot], $questionstats[$slot]->s, $reporturl, $qubaids);
// Back to overview link.
echo $OUTPUT->box('<a href="' . $reporturl->out() . '">' .
print_error('questiondoesnotexist', 'question');
}
- $this->output_individual_question_data($quiz, $subquestions[$qid]);
- $this->output_individual_question_response_analysis(
- $subquestions[$qid], $reporturl, $qubaids);
+ $this->output_individual_question_data($quiz, $subquestionstats[$qid]);
+ $this->output_individual_question_response_analysis($subquestionstats[$qid]->question,
+ $subquestionstats[$qid]->s, $reporturl, $qubaids);
// Back to overview link.
echo $OUTPUT->box('<a href="' . $reporturl->out() . '">' .
} else if ($this->table->is_downloading()) {
// Downloading overview report.
$this->download_quiz_info_table($quizinfo);
- $this->output_quiz_structure_analysis_table($quizstats->s(), $questions, $subquestions);
+ $this->output_quiz_structure_analysis_table($quizstats->s(), $questionstats, $subquestionstats);
$this->table->finish_output();
} else {
echo $this->output_quiz_info_table($quizinfo);
if ($quizstats->s()) {
echo $OUTPUT->heading(get_string('quizstructureanalysis', 'quiz_statistics'));
- $this->output_quiz_structure_analysis_table($quizstats->s(), $questions, $subquestions);
+ $this->output_quiz_structure_analysis_table($quizstats->s(), $questionstats, $subquestionstats);
$this->output_statistics_graph($quiz->id, $currentgroup, $useallattempts);
}
}
* Display the statistical and introductory information about a question.
* Only called when not downloading.
* @param object $quiz the quiz settings.
- * @param object $question the question to report on.
+ * @param \core_question\statistics\questions\calculated $questionstat the question to report on.
* @param moodle_url $reporturl the URL to resisplay this report.
* @param object $quizstats Holds the quiz statistics.
*/
- protected function output_individual_question_data($quiz, $question) {
+ protected function output_individual_question_data($quiz, $questionstat) {
global $OUTPUT;
// On-screen display. Show a summary of the question's place in the quiz,
// and the question statistics.
- $datumfromtable = $this->table->format_row($question);
+ $datumfromtable = $this->table->format_row($questionstat);
// Set up the question info table.
$questioninfotable = new html_table();
$questioninfotable->data = array();
$questioninfotable->data[] = array(get_string('modulename', 'quiz'), $quiz->name);
$questioninfotable->data[] = array(get_string('questionname', 'quiz_statistics'),
- $question->name.' '.$datumfromtable['actions']);
+ $questionstat->question->name.' '.$datumfromtable['actions']);
$questioninfotable->data[] = array(get_string('questiontype', 'quiz_statistics'),
$datumfromtable['icon'] . ' ' .
- question_bank::get_qtype($question->qtype, false)->menu_name() . ' ' .
+ question_bank::get_qtype($questionstat->question->qtype, false)->menu_name() . ' ' .
$datumfromtable['icon']);
$questioninfotable->data[] = array(get_string('positions', 'quiz_statistics'),
- $question->_stats->positions);
+ $questionstat->positions);
// Set up the question statistics table.
$questionstatstable = new html_table();
// Display the various bits.
echo $OUTPUT->heading(get_string('questioninformation', 'quiz_statistics'));
echo html_writer::table($questioninfotable);
- echo $this->render_question_text($question);
+ echo $this->render_question_text($questionstat->question);
echo $OUTPUT->heading(get_string('questionstatistics', 'quiz_statistics'));
echo html_writer::table($questionstatstable);
}
* @param moodle_url $reporturl the URL to resisplay this report.
* @param qubaid_condition $qubaids
*/
- protected function output_individual_question_response_analysis($question,
- $reporturl, $qubaids) {
+ protected function output_individual_question_response_analysis($question, $s, $reporturl, $qubaids) {
global $OUTPUT;
if (!question_bank::get_qtype($question->qtype, false)->can_analyse_responses()) {
}
}
- $responesstats = new question_response_analyser($question);
+ $responesstats = new \core_question\statistics\responses\analyser($question);
$responesstats->load_cached($qubaids);
- $qtable->question_setup($reporturl, $question, $responesstats);
+ $qtable->question_setup($reporturl, $question, $s, $responesstats);
if ($this->table->is_downloading()) {
$exportclass->output_headers($qtable->headers);
}
/**
* Output the table that lists all the questions in the quiz with their statistics.
* @param int $s number of attempts.
- * @param array $questions the questions in the quiz.
- * @param array $subquestions the subquestions of any random questions.
+ * @param \core_question\statistics\questions\calculated[] $questionstats the stats for the main questions in the quiz.
+ * @param \core_question\statistics\questions\calculated_for_subquestion[] $subquestionstats the stats of any random questions.
*/
- protected function output_quiz_structure_analysis_table($s, $questions, $subquestions) {
+ protected function output_quiz_structure_analysis_table($s, $questionstats, $subquestionstats) {
if (!$s) {
return;
}
- foreach ($questions as $question) {
- // Output the data for this questions.
- $this->table->add_data_keyed($this->table->format_row($question));
+ foreach ($questionstats as $questionstat) {
+ // Output the data for these question statistics.
+ $this->table->add_data_keyed($this->table->format_row($questionstat));
- if (empty($question->_stats->subquestions)) {
+ if (empty($questionstat->subquestions)) {
continue;
}
// And its subquestions, if it has any.
- $subitemstodisplay = explode(',', $question->_stats->subquestions);
+ $subitemstodisplay = explode(',', $questionstat->subquestions);
foreach ($subitemstodisplay as $subitemid) {
- $subquestions[$subitemid]->maxmark = $question->maxmark;
- $this->table->add_data_keyed($this->table->format_row($subquestions[$subitemid]));
+ $subquestionstats[$subitemid]->maxmark = $questionstat->maxmark;
+ $this->table->add_data_keyed($this->table->format_row($subquestionstats[$subitemid]));
}
}
* @param array $questions question definitions.
* @return array with 4 elements:
* - $quizstats The statistics for overall attempt scores.
- * - $questions The questions, with an additional _stats field.
- * - $subquestions The subquestions, if any, with an additional _stats field.
- * - $s Number of attempts included in the stats.
+ * - $questionstats array of \core_question\statistics\questions\calculated objects keyed by slot.
+ * - $subquestionstats array of \core_question\statistics\questions\calculated_for_subquestion objects keyed by question id.
*/
protected function get_quiz_and_questions_stats($quiz, $currentgroup, $useallattempts, $groupstudents, $questions) {
$qubaids = quiz_statistics_qubaids_condition($quiz->id, $currentgroup, $groupstudents, $useallattempts);
-
- $qstats = new question_statistics($questions);
+ $qcalc = new \core_question\statistics\questions\calculator($questions);
$quizcalc = new quiz_statistics_calculator();
if ($quizcalc->get_last_calculated_time($qubaids) === false) {
// Recalculate now.
- $qstats->calculate($qubaids);
+ list($questionstats, $subquestionstats) = $qcalc->calculate($qubaids);
$quizstats = $quizcalc->calculate($quiz->id, $currentgroup, $useallattempts,
- $groupstudents, count($questions), $qstats->get_sum_of_mark_variance());
+ $groupstudents, count($questions), $qcalc->get_sum_of_mark_variance());
- $questions = $qstats->questions;
- $subquestions = $qstats->subquestions;
if ($quizstats->s()) {
- $this->calculate_responses_for_all_questions_and_subquestions($qubaids, $questions, $subquestions);
+ $this->calculate_responses_for_all_questions_and_subquestions($qubaids, $questions, $subquestionstats);
}
} else {
$quizstats = $quizcalc->get_cached($qubaids);
- $qstats->get_cached($qubaids);
- $questions = $qstats->questions;
- $subquestions = $qstats->subquestions;
+ list($questionstats, $subquestionstats) = $qcalc->get_cached($qubaids);
}
- return array($quizstats, $questions, $subquestions);
+ return array($quizstats, $questionstats, $subquestionstats);
}
- protected function calculate_responses_for_all_questions_and_subquestions($qubaids, $questions, $subquestions) {
+ protected function calculate_responses_for_all_questions_and_subquestions($qubaids, $questions, $subquestionstats) {
$done = array();
foreach ($questions as $question) {
}
$done[$question->id] = 1;
- $responesstats = new question_response_analyser($question);
+ $responesstats = new \core_question\statistics\responses\analyser($question);
$responesstats->calculate($qubaids);
}
- foreach ($subquestions as $question) {
- if (!question_bank::get_qtype($question->qtype, false)->can_analyse_responses() ||
- isset($done[$question->id])) {
+ foreach ($subquestionstats as $subquestionstat) {
+ if (!question_bank::get_qtype($subquestionstat->question->qtype, false)->can_analyse_responses() ||
+ isset($done[$subquestionstat->question->id])) {
continue;
}
- $done[$question->id] = 1;
+ $done[$subquestionstat->question->id] = 1;
- $responesstats = new question_response_analyser($question);
+ $responesstats = new \core_question\statistics\responses\analyser($subquestionstat->question);
$responesstats->calculate($qubaids);
}
}
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class quiz_statistics_question_table extends flexible_table {
- /** @var object this question with a _stats field. */
+ /** @var object this question. */
protected $questiondata;
/**
* Constructor.
- * @param $qid the id of the particular question whose statistics are being
+ * @param int $qid the id of the particular question whose statistics are being
* displayed.
*/
public function __construct($qid) {
}
/**
- * Set up the columns and headers and other properties of the table and then
- * call flexible_table::setup() method.
- *
- * @param moodle_url $reporturl the URL to redisplay this report.
- * @param object $question a question with a _stats field
- * @param bool $hassubqs
+ * @param moodle_url $reporturl
+ * @param object $questiondata
+ * @param integer $s number of attempts on this question.
+ * @param \core_question\statistics\responses\analyser $responesstats
*/
- public function question_setup($reporturl, $questiondata,
- question_response_analyser $responesstats) {
+ public function question_setup($reporturl, $questiondata, $s, \core_question\statistics\responses\analyser $responesstats) {
$this->questiondata = $questiondata;
+ $this->s = $s;
$this->define_baseurl($reporturl->out());
$this->collapsible(false);
* @return string contents of this table cell.
*/
protected function col_frequency($response) {
- if (!$this->questiondata->_stats->s) {
+ if (!$this->s) {
return '';
}
- return $this->format_percentage($response->count / $this->questiondata->_stats->s);
+ return $this->format_percentage($response->count / $this->s);
}
}
/**
* The question number.
- * @param object $question containst the data to display.
+ * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
* @return string contents of this table cell.
*/
- protected function col_number($question) {
- if ($question->_stats->subquestion) {
+ protected function col_number($questionstat) {
+ if ($questionstat->subquestion) {
return '';
}
- return $question->number;
+ return $questionstat->question->number;
}
/**
* The question type icon.
- * @param object $question containst the data to display.
+ * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
* @return string contents of this table cell.
*/
- protected function col_icon($question) {
- return print_question_icon($question, true);
+ protected function col_icon($questionstat) {
+ return print_question_icon($questionstat->question, true);
}
/**
* Actions that can be performed on the question by this user (e.g. edit or preview).
- * @param object $question containst the data to display.
+ * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
* @return string contents of this table cell.
*/
- protected function col_actions($question) {
- return quiz_question_action_icons($this->quiz, $this->cmid, $question, $this->baseurl);
+ protected function col_actions($questionstat) {
+ return quiz_question_action_icons($this->quiz, $this->cmid, $questionstat->question, $this->baseurl);
}
/**
* The question type name.
- * @param object $question containst the data to display.
+ *
+ * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
* @return string contents of this table cell.
*/
- protected function col_qtype($question) {
- return question_bank::get_qtype_name($question->qtype);
+ protected function col_qtype($questionstat) {
+ return question_bank::get_qtype_name($questionstat->question->qtype);
}
/**
* The question name.
- * @param object $question containst the data to display.
+ *
+ * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
* @return string contents of this table cell.
*/
- protected function col_name($question) {
- $name = $question->name;
+ protected function col_name($questionstat) {
+ $name = $questionstat->question->name;
if ($this->is_downloading()) {
return $name;
}
$url = null;
- if ($question->_stats->subquestion) {
- $url = new moodle_url($this->baseurl, array('qid' => $question->id));
- } else if ($question->_stats->slot && $question->qtype != 'random') {
- $url = new moodle_url($this->baseurl, array('slot' => $question->_stats->slot));
+ if ($questionstat->subquestion) {
+ $url = new moodle_url($this->baseurl, array('qid' => $questionstat->questionid));
+ } else if ($questionstat->slot && $questionstat->question->qtype != 'random') {
+ $url = new moodle_url($this->baseurl, array('slot' => $questionstat->slot));
}
if ($url) {
array('title' => get_string('detailedanalysis', 'quiz_statistics')));
}
- if ($this->is_dubious_question($question)) {
+ if ($this->is_dubious_question($questionstat)) {
$name = html_writer::tag('div', $name, array('class' => 'dubious'));
}
/**
* The number of attempts at this question.
- * @param object $question containst the data to display.
+ *
+ * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
* @return string contents of this table cell.
*/
- protected function col_s($question) {
- if (!isset($question->_stats->s)) {
+ protected function col_s($questionstat) {
+ if (!isset($questionstat->s)) {
return 0;
}
- return $question->_stats->s;
+ return $questionstat->s;
}
/**
* The facility index (average fraction).
- * @param object $question containst the data to display.
+ * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
* @return string contents of this table cell.
*/
- protected function col_facility($question) {
- if (is_null($question->_stats->facility)) {
+ protected function col_facility($questionstat) {
+ if (is_null($questionstat->facility)) {
return '';
}
- return number_format($question->_stats->facility*100, 2) . '%';
+ return number_format($questionstat->facility*100, 2) . '%';
}
/**
* The standard deviation of the fractions.
- * @param object $question containst the data to display.
+ * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
* @return string contents of this table cell.
*/
- protected function col_sd($question) {
- if (is_null($question->_stats->sd) || $question->_stats->maxmark == 0) {
+ protected function col_sd($questionstat) {
+ if (is_null($questionstat->sd) || $questionstat->maxmark == 0) {
return '';
}
- return number_format($question->_stats->sd*100 / $question->_stats->maxmark, 2) . '%';
+ return number_format($questionstat->sd*100 / $questionstat->maxmark, 2) . '%';
}
/**
* An estimate of the fraction a student would get by guessing randomly.
- * @param object $question containst the data to display.
+ * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
* @return string contents of this table cell.
*/
- protected function col_random_guess_score($question) {
- if (is_null($question->_stats->randomguessscore)) {
+ protected function col_random_guess_score($questionstat) {
+ if (is_null($questionstat->randomguessscore)) {
return '';
}
- return number_format($question->_stats->randomguessscore * 100, 2).'%';
+ return number_format($questionstat->randomguessscore * 100, 2).'%';
}
/**
* The intended question weight. Maximum mark for the question as a percentage
* of maximum mark for the quiz. That is, the indended influence this question
* on the student's overall mark.
- * @param object $question containst the data to display.
+ * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
* @return string contents of this table cell.
*/
- protected function col_intended_weight($question) {
- return quiz_report_scale_summarks_as_percentage(
- $question->_stats->maxmark, $this->quiz);
+ protected function col_intended_weight($questionstat) {
+ return quiz_report_scale_summarks_as_percentage($questionstat->maxmark, $this->quiz);
}
/**
* The effective question weight. That is, an estimate of the actual
* influence this question has on the student's overall mark.
- * @param object $question containst the data to display.
+ * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
* @return string contents of this table cell.
*/
- protected function col_effective_weight($question) {
+ protected function col_effective_weight($questionstat) {
global $OUTPUT;
- if ($question->_stats->subquestion) {
+ if ($questionstat->subquestion) {
return '';
}
- if ($question->_stats->negcovar) {
+ if ($questionstat->negcovar) {
$negcovar = get_string('negcovar', 'quiz_statistics');
if (!$this->is_downloading()) {
return $negcovar;
}
- return number_format($question->_stats->effectiveweight, 2) . '%';
+ return number_format($questionstat->effectiveweight, 2) . '%';
}
/**
* Discrimination index. This is the product moment correlation coefficient
- * between the fraction for this qestion, and the average fraction for the
+ * between the fraction for this question, and the average fraction for the
* other questions in this quiz.
- * @param object $question containst the data to display.
+ * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
* @return string contents of this table cell.
*/
- protected function col_discrimination_index($question) {
- if (!is_numeric($question->_stats->discriminationindex)) {
- return $question->_stats->discriminationindex;
+ protected function col_discrimination_index($questionstat) {
+ if (!is_numeric($questionstat->discriminationindex)) {
+ return $questionstat->discriminationindex;
}
- return number_format($question->_stats->discriminationindex, 2) . '%';
+ return number_format($questionstat->discriminationindex, 2) . '%';
}
/**
* Discrimination efficiency, similar to, but different from, the Discrimination index.
- * @param object $question containst the data to display.
+ *
+ * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
* @return string contents of this table cell.
*/
- protected function col_discriminative_efficiency($question) {
- if (!is_numeric($question->_stats->discriminativeefficiency)) {
+ protected function col_discriminative_efficiency($questionstat) {
+ if (!is_numeric($questionstat->discriminativeefficiency)) {
return '';
}
- return number_format($question->_stats->discriminativeefficiency, 2) . '%';
+ return number_format($questionstat->discriminativeefficiency, 2) . '%';
}
/**
* This method encapsulates the test for wheter a question should be considered dubious.
- * @param object question the question object with a property _stats which
- * includes all the stats for the question.
+ * @param \core_question\statistics\questions\calculated $questionstat stats for the question.
* @return bool is this question possibly not pulling it's weight?
*/
- protected function is_dubious_question($question) {
- if (!is_numeric($question->_stats->discriminativeefficiency)) {
+ protected function is_dubious_question($questionstat) {
+ if (!is_numeric($questionstat->discriminativeefficiency)) {
return false;
}
- return $question->_stats->discriminativeefficiency < 15;
+ return $questionstat->discriminativeefficiency < 15;
}
public function wrap_html_start() {
global $CFG;
require_once($CFG->libdir . '/questionlib.php');
-require_once($CFG->dirroot . '/question/engine/statistics.php');
require_once($CFG->dirroot . '/mod/quiz/locallib.php');
require_once($CFG->dirroot . '/mod/quiz/report/reportlib.php');
* @copyright 2010 The Open University
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
-class testable_question_statistics extends question_statistics {
+class testable_question_statistics extends \core_question\statistics\questions\calculator {
+
+ /**
+ * @var object[]
+ */
+ protected $lateststeps;
+
public function set_step_data($states) {
$this->lateststeps = $states;
}
// Data is taken from questions mostly generated by
// contrib/tools/generators/generator.php.
$questions = $this->get_records_from_csv(__DIR__.'/fixtures/mdl_question.csv');
- $this->qstats = new testable_question_statistics($questions, 22, 10045.45455);
- $this->qstats->set_step_data($steps);
- $this->qstats->calculate(null);
+ $calculator = new testable_question_statistics($questions);
+ $calculator->set_step_data($steps);
+ list($this->qstats, ) = $calculator->calculate(null);
// Values expected are taken from contrib/tools/quiz_tools/stats.xls.
$facility = array(0, 0, 0, 0, null, null, null, 41.19318182, 81.36363636,
}
public function qstats_q_fields($fieldname, $values, $multiplier=1) {
- foreach ($this->qstats->questions as $question) {
+ foreach ($this->qstats as $qstat) {
$value = array_shift($values);
if ($value !== null) {
- $this->assertEquals($question->_stats->{$fieldname} * $multiplier,
+ $this->assertEquals($qstat->{$fieldname} * $multiplier,
$value, '', 1E-6);
} else {
- $this->assertEquals($question->_stats->{$fieldname} * $multiplier, $value);
+ $this->assertEquals($qstat->{$fieldname} * $multiplier, $value);
}
}
}
$this->check_attempts_results($csvdata['results'], $attemptids);
$this->report = new testable_quiz_statistics_report();
- list($quizstats, $questions, $subquestions) = $this->report->get_stats($this->quiz);
+ list($quizstats, $questionstats, $subquestionstats) = $this->report->get_stats($this->quiz);
// These quiz stats and the question stats found in qstats00.csv were calculated independently in spreadsheet which is
// available in open document or excel format here :
}
$slot = $slotqstats['slot'];
$delta = abs($slotqstat) * $precision;
- $actual = $questions[$slot]->_stats->{$statname};
+ $actual = $questionstats[$slot]->{$statname};
$this->assertEquals(floatval($slotqstat), $actual, "$statname for slot $slot", $delta);
}
}
--- /dev/null
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Question statistics calculations class. Used in the quiz statistics report but also available for use elsewhere.
+ *
+ * @package core
+ * @subpackage questionbank
+ * @copyright 2013 Open University
+ * @author Jamie Pratt <me@jamiep.org>
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\statistics\questions;
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * This class is used to return the stats as calculated by {@link \core_question\statistics\questions\calculator}
+ *
+ * @copyright 2013 Open University
+ * @author Jamie Pratt <me@jamiep.org>
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class calculated {
+
+ public $questionid;
+
+
+ // These first fields are the final fields cached in the db and shown in reports.
+
+ // See : http://docs.moodle.org/dev/Quiz_statistics_calculations#Position_statistics .
+
+ public $slot = null;
+
+ /**
+ * @var bool is this a sub question.
+ */
+ public $subquestion = false;
+
+ /**
+ * @var int total attempts at this question.
+ */
+ public $s = 0;
+
+ /**
+ * @var float effective weight of this question.
+ */
+ public $effectiveweight;
+
+ /**
+ * @var bool is covariance of this questions mark with other question marks negative?
+ */
+ public $negcovar;
+
+ /**
+ * @var float
+ */
+ public $discriminationindex;
+
+ /**
+ * @var float
+ */
+ public $discriminativeefficiency;
+
+ /**
+ * @var float standard deviation
+ */
+ public $sd;
+
+ /**
+ * @var float
+ */
+ public $facility;
+
+ /**
+ * @var float max mark achievable for this question.
+ */
+ public $maxmark;
+
+ /**
+ * @var string comma separated list of the positions in which this question appears.
+ */
+ public $positions;
+
+ /**
+ * @var null|float The average score that students would have got by guessing randomly. Or null if not calculable.
+ */
+ public $randomguessscore = null;
+
+ // End of fields in db.
+
+ protected $fieldsindb = array('questionid', 'slot', 'subquestion', 's', 'effectiveweight', 'negcovar', 'discriminationindex',
+ 'discriminativeefficiency', 'sd', 'facility', 'subquestions', 'maxmark', 'positions', 'randomguessscore');
+
+ // Fields used for intermediate calculations.
+
+ public $totalmarks = 0;
+
+ public $totalothermarks = 0;
+
+ public $markvariancesum = 0;
+
+ public $othermarkvariancesum = 0;
+
+ public $covariancesum = 0;
+
+ public $covariancemaxsum = 0;
+
+ public $subquestions = '';
+
+ public $covariancewithoverallmarksum = 0;
+
+ public $markarray = array();
+
+ public $othermarksarray = array();
+
+ public $markaverage;
+
+ public $othermarkaverage;
+
+ public $markvariance;
+ public $othermarkvariance;
+ public $covariance;
+ public $covariancemax;
+ public $covariancewithoverallmark;
+
+ /**
+ * @var object full question data
+ */
+ public $question;
+
+ /**
+ * Set if this record has been retrieved from cache. This is the time that the statistics were calculated.
+ *
+ * @var integer
+ */
+ public $timemodified;
+
+ /**
+ * Cache calculated stats stored in this object in 'question_statistics' table.
+ *
+ * @param \qubaid_condition $qubaids
+ */
+ public function cache($qubaids) {
+ global $DB;
+ $toinsert = new \stdClass();
+ $toinsert->hashcode = $qubaids->get_hash_code();
+ $toinsert->timemodified = time();
+ foreach ($this->fieldsindb as $field) {
+ $toinsert->{$field} = $this->{$field};
+ }
+ $DB->insert_record('question_statistics', $toinsert, false);
+ }
+
+ /**
+ * @param object $record Given a record from 'question_statistics' copy stats from record to properties.
+ */
+ public function populate_from_record($record) {
+ foreach ($this->fieldsindb as $field) {
+ $this->$field = $record->$field;
+ }
+ $this->timemodified = $record->timemodified;
+ }
+
+
+}
--- /dev/null
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Class for storing calculated sub question statistics and intermediate calculation values.
+ *
+ * @package core_question
+ * @copyright 2013 The Open University
+ * @author James Pratt me@jamiep.org
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace core_question\statistics\questions;
+defined('MOODLE_INTERNAL') || die();
+
+class calculated_for_subquestion extends calculated {
+ public $subquestion = true;
+
+ public $usedin = array();
+
+ public $differentweights = false;
+
+ public $negcovar = 0;
+}
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
- * Question statistics calculations class. Used in the quiz statistics report but also available for use elsewhere.
+ * Question statistics calculator class. Used in the quiz statistics report but also available for use elsewhere.
*
* @package core
* @subpackage questionbank
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
-
+namespace core_question\statistics\questions;
defined('MOODLE_INTERNAL') || die();
-
/**
* This class has methods to compute the question statistics from the raw data.
*
* @author Jamie Pratt <me@jamiep.org>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
-class question_statistics {
- public $questions;
- public $subquestions = array();
-
- protected $summarksavg;
-
- protected $sumofmarkvariance = 0;
- protected $randomselectors = array();
+class calculator {
/**
- * Constructor.
- *
- * @param $questions array the main questions indexed by slot.
+ * @var calculated[]
*/
- public function __construct($questions) {
- foreach ($questions as $slot => $question) {
- $question->_stats = $this->make_blank_question_stats();
- $question->_stats->questionid = $question->id;
- $question->_stats->slot = $slot;
- }
-
- $this->questions = $questions;
- }
+ public $questionstats = array();
/**
- * @return object ready to hold all the question statistics.
+ * @var calculated_for_subquestion[]
*/
- protected function make_blank_question_stats() {
- $stats = new stdClass();
- $stats->slot = null;
- $stats->s = 0;
- $stats->totalmarks = 0;
- $stats->totalothermarks = 0;
- $stats->markvariancesum = 0;
- $stats->othermarkvariancesum = 0;
- $stats->covariancesum = 0;
- $stats->covariancemaxsum = 0;
- $stats->subquestion = false;
- $stats->subquestions = '';
- $stats->covariancewithoverallmarksum = 0;
- $stats->randomguessscore = null;
- $stats->markarray = array();
- $stats->othermarksarray = array();
- return $stats;
- }
+ public $subquestionstats = array();
/**
- * @param $qubaids qubaid_condition
- * @return array with three items
- * - $lateststeps array of latest step data for the question usages
- * - $summarks array of total marks for each usage, indexed by usage id
- * - $summarksavg the average of the total marks over all the usages
+ * @var float
*/
- protected function get_latest_steps($qubaids) {
- $dm = new question_engine_data_mapper();
+ protected $sumofmarkvariance = 0;
- $fields = " qas.id,
- qa.questionusageid,
- qa.questionid,
- qa.slot,
- qa.maxmark,
- qas.fraction * qa.maxmark as mark";
+ protected $randomselectors = array();
- $lateststeps = $dm->load_questions_usages_latest_steps($qubaids, array_keys($this->questions), $fields);
- $summarks = array();
- if ($lateststeps) {
- foreach ($lateststeps as $step) {
- if (!isset($summarks[$step->questionusageid])) {
- $summarks[$step->questionusageid] = 0;
- }
- $summarks[$step->questionusageid] += $step->mark;
- }
- $summarksavg = array_sum($summarks) / count($summarks);
- } else {
- $summarksavg = null;
+ /**
+ * Constructor.
+ *
+ * @param object[] questions to analyze, keyed by slot, also analyses sub questions for random questions.
+ * we expect some extra fields - slot, maxmark and number on the full question data objects.
+ */
+ public function __construct($questions) {
+ foreach ($questions as $slot => $question) {
+ $this->questionstats[$slot] = new calculated();
+ $this->questionstats[$slot]->questionid = $question->id;
+ $this->questionstats[$slot]->question = $question;
+ $this->questionstats[$slot]->slot = $slot;
+ $this->questionstats[$slot]->positions = $question->number;
+ $this->questionstats[$slot]->maxmark = $question->maxmark;
+ $this->questionstats[$slot]->randomguessscore = $this->get_random_guess_score($question);
}
-
- return array($lateststeps, $summarks, $summarksavg);
}
/**
- * @param $qubaids qubaid_condition
+ * @param $qubaids \qubaid_condition
+ * @return array containing two arrays calculated[] and calculated_for_subquestion[].
*/
public function calculate($qubaids) {
set_time_limit(0);
list($lateststeps, $summarks, $summarksavg) = $this->get_latest_steps($qubaids);
if ($lateststeps) {
- $subquestionstats = array();
// Compute the statistics of position, and for random questions, work
// out which questions appear in which positions.
foreach ($lateststeps as $step) {
- $this->initial_steps_walker($step, $this->questions[$step->slot]->_stats, $summarks);
+ $this->initial_steps_walker($step, $this->questionstats[$step->slot], $summarks);
// If this is a random question what is the real item being used?
- if ($step->questionid != $this->questions[$step->slot]->id) {
- if (!isset($subquestionstats[$step->questionid])) {
- $subquestionstats[$step->questionid] = $this->make_blank_question_stats();
- $subquestionstats[$step->questionid]->questionid = $step->questionid;
- $subquestionstats[$step->questionid]->usedin = array();
- $subquestionstats[$step->questionid]->subquestion = true;
- $subquestionstats[$step->questionid]->differentweights = false;
- $subquestionstats[$step->questionid]->maxmark = $step->maxmark;
- } else if ($subquestionstats[$step->questionid]->maxmark != $step->maxmark) {
- $subquestionstats[$step->questionid]->differentweights = true;
+ if ($step->questionid != $this->questionstats[$step->slot]->questionid) {
+ if (!isset($this->subquestionstats[$step->questionid])) {
+ $this->subquestionstats[$step->questionid] = new calculated_for_subquestion();
+ $this->subquestionstats[$step->questionid]->questionid = $step->questionid;
+ $this->subquestionstats[$step->questionid]->maxmark = $step->maxmark;
+ } else if ($this->subquestionstats[$step->questionid]->maxmark != $step->maxmark) {
+ $this->subquestionstats[$step->questionid]->differentweights = true;
}
- $this->initial_steps_walker($step, $subquestionstats[$step->questionid], $summarks, false);
+ $this->initial_steps_walker($step, $this->subquestionstats[$step->questionid], $summarks, false);
- $number = $this->questions[$step->slot]->number;
- $subquestionstats[$step->questionid]->usedin[$number] = $number;
+ $number = $this->questionstats[$step->slot]->question->number;
+ $this->subquestionstats[$step->questionid]->usedin[$number] = $number;
- $randomselectorstring = $this->questions[$step->slot]->category .
- '/' . $this->questions[$step->slot]->questiontext;
+ $randomselectorstring = $this->questionstats[$step->slot]->question->category. '/'
+ .$this->questionstats[$step->slot]->question->questiontext;
if (!isset($this->randomselectors[$randomselectorstring])) {
$this->randomselectors[$randomselectorstring] = array();
}
- $this->randomselectors[$randomselectorstring][$step->questionid] =
- $step->questionid;
+ $this->randomselectors[$randomselectorstring][$step->questionid] = $step->questionid;
}
}
}
// Compute the statistics of question id, if we need any.
- $this->subquestions = question_load_questions(array_keys($subquestionstats));
- foreach ($this->subquestions as $qid => $subquestion) {
- $subquestion->_stats = $subquestionstats[$qid];
- $subquestion->maxmark = $subquestion->_stats->maxmark;
- $subquestion->_stats->randomguessscore = $this->get_random_guess_score($subquestion);
+ $subquestions = question_load_questions(array_keys($this->subquestionstats));
+ foreach ($subquestions as $qid => $subquestion) {
+ $this->subquestionstats[$qid]->question = $subquestion;
+ $this->subquestionstats[$qid]->question->maxmark = $this->subquestionstats[$qid]->maxmark;
+ $this->subquestionstats[$qid]->randomguessscore = $this->get_random_guess_score($subquestion);
- $this->initial_question_walker($subquestion->_stats);
+ $this->initial_question_walker($this->subquestionstats[$qid]);
- if ($subquestionstats[$qid]->differentweights) {
+ if ($this->subquestionstats[$qid]->differentweights) {
// TODO output here really sucks, but throwing is too severe.
global $OUTPUT;
- echo $OUTPUT->notification(
- get_string('erroritemappearsmorethanoncewithdifferentweight',
- 'quiz_statistics', $this->subquestions[$qid]->name));
+ $name = $this->subquestionstats[$qid]->question->name;
+ echo $OUTPUT->notification( get_string('erroritemappearsmorethanoncewithdifferentweight',
+ 'quiz_statistics', $name));
}
- if ($subquestion->_stats->usedin) {
- sort($subquestion->_stats->usedin, SORT_NUMERIC);
- $subquestion->_stats->positions = implode(',', $subquestion->_stats->usedin);
+ if ($this->subquestionstats[$qid]->usedin) {
+ sort($this->subquestionstats[$qid]->usedin, SORT_NUMERIC);
+ $this->subquestionstats[$qid]->positions = implode(',', $this->subquestionstats[$qid]->usedin);
} else {
- $subquestion->_stats->positions = '';
+ $this->subquestionstats[$qid]->positions = '';
}
}
// This cannot be a foreach loop because we need to have both
// $question and $nextquestion available, but apart from that it is
// foreach ($this->questions as $qid => $question).
- reset($this->questions);
- while (list($slot, $question) = each($this->questions)) {
- $nextquestion = current($this->questions);
- $question->_stats->positions = $question->number;
- $question->_stats->maxmark = $question->maxmark;
- $question->_stats->randomguessscore = $this->get_random_guess_score($question);
-
- $this->initial_question_walker($question->_stats);
-
- if ($question->qtype == 'random') {
- $randomselectorstring = $question->category.'/'.$question->questiontext;
- if ($nextquestion && $nextquestion->qtype == 'random') {
- $nextrandomselectorstring = $nextquestion->category . '/' .
- $nextquestion->questiontext;
+ reset($this->questionstats);
+ while (list($slot, $questionstat) = each($this->questionstats)) {
+ $nextquestionstats = current($this->questionstats);
+
+ $this->initial_question_walker($questionstat);
+
+ if ($questionstat->question->qtype == 'random') {
+ $randomselectorstring = $questionstat->question->category .'/'. $questionstat->question->questiontext;
+ if ($nextquestionstats && $nextquestionstats->question->qtype == 'random') {
+ $nextrandomselectorstring =
+ $nextquestionstats->question->category .'/'. $nextquestionstats->question->questiontext;
if ($randomselectorstring == $nextrandomselectorstring) {
continue; // Next loop iteration.
}
}
if (isset($this->randomselectors[$randomselectorstring])) {
- $question->_stats->subquestions = implode(',',
- $this->randomselectors[$randomselectorstring]);
+ $questionstat->subquestions = implode(',', $this->randomselectors[$randomselectorstring]);
}
}
}
// Go through the records one more time.
foreach ($lateststeps as $step) {
- $this->secondary_steps_walker($step, $this->questions[$step->slot]->_stats, $summarks, $summarksavg);
+ $this->secondary_steps_walker($step, $this->questionstats[$step->slot], $summarks, $summarksavg);
- if ($this->questions[$step->slot]->qtype == 'random') {
- $this->secondary_steps_walker($step, $this->subquestions[$step->questionid]->_stats, $summarks, $summarksavg);
+ if ($this->questionstats[$step->slot]->subquestion) {
+ $this->secondary_steps_walker($step, $this->subquestionstats[$step->questionid], $summarks, $summarksavg);
}
}
$sumofcovariancewithoverallmark = 0;
- foreach ($this->questions as $slot => $question) {
- $this->secondary_question_walker($question->_stats);
+ foreach ($this->questionstats as $questionstat) {
+ $this->secondary_question_walker($questionstat);
- $this->sumofmarkvariance += $question->_stats->markvariance;
+ $this->sumofmarkvariance += $questionstat->markvariance;
- if ($question->_stats->covariancewithoverallmark >= 0) {
- $sumofcovariancewithoverallmark +=
- sqrt($question->_stats->covariancewithoverallmark);
- $question->_stats->negcovar = 0;
- } else {
- $question->_stats->negcovar = 1;
+ if ($questionstat->covariancewithoverallmark >= 0) {
+ $sumofcovariancewithoverallmark += sqrt($questionstat->covariancewithoverallmark);
}
}
- foreach ($this->subquestions as $subquestion) {
- $this->secondary_question_walker($subquestion->_stats);
+ foreach ($this->subquestionstats as $subquestionstat) {
+ $this->secondary_question_walker($subquestionstat);
}
- foreach ($this->questions as $question) {
+ foreach ($this->questionstats as $questionstat) {
if ($sumofcovariancewithoverallmark) {
- if ($question->_stats->negcovar) {
- $question->_stats->effectiveweight = null;
+ if ($questionstat->negcovar) {
+ $questionstat->effectiveweight = null;
} else {
- $question->_stats->effectiveweight = 100 *
- sqrt($question->_stats->covariancewithoverallmark) /
+ $questionstat->effectiveweight = 100 * sqrt($questionstat->covariancewithoverallmark) /
$sumofcovariancewithoverallmark;
}
} else {
- $question->_stats->effectiveweight = null;
+ $questionstat->effectiveweight = null;
}
}
$this->cache_stats($qubaids);
}
-
-
+ return array($this->questionstats, $this->subquestionstats);
}
/**
- * @param $qubaids qubaid_condition
+ * Load cached statistics from the database.
+ *
+ * @param $qubaids \qubaid_condition
+ * @return array containing two arrays calculated[] and calculated_for_subquestion[].
*/
- protected function cache_stats($qubaids) {
+ public function get_cached($qubaids) {
global $DB;
- $cachetime = time();
- foreach ($this->questions as $question) {
- $question->_stats->hashcode = $qubaids->get_hash_code();
- $question->_stats->timemodified = $cachetime;
- $DB->insert_record('question_statistics', $question->_stats, false);
+ $timemodified = time() - self::TIME_TO_CACHE;
+ $questionstatrecs = $DB->get_record_select('question_statistics', 'hashcode = ? AND timemodified > ?',
+ array($qubaids->get_hash_code(), $timemodified));
+
+ $questionids = array();
+ foreach ($questionstatrecs as $fromdb) {
+ if (!$fromdb->slot) {
+ $questionids[] = $fromdb->questionid;
+ }
}
+ $subquestions = question_load_questions($questionids);
+ foreach ($questionstatrecs as $fromdb) {
+ if ($fromdb->slot) {
+ $this->questionstats[$fromdb->slot]->populate_from_record($fromdb);
+ // Array created in constructor and populated from question.
+ } else {
+ $this->subquestionstats[$fromdb->questionid] = new calculated_for_subquestion();
+ $this->subquestionstats[$fromdb->questionid]->populate_from_record($fromdb);
+ $this->subquestionstats[$fromdb->questionid]->question = $subquestions[$fromdb->questionid];
+ }
+ }
+ return array($this->questionstats, $this->subquestionstats);
+ }
- foreach ($this->subquestions as $subquestion) {
- $subquestion->_stats->hashcode = $qubaids->get_hash_code();
- $subquestion->_stats->timemodified = $cachetime;
- $DB->insert_record('question_statistics', $subquestion->_stats, false);
+ /**
+ * Find time of non-expired statistics in the database.
+ *
+ * @param $qubaids \qubaid_condition
+ * @return integer|boolean Time of cached record that matches this qubaid_condition or false is non found.
+ */
+ public function get_last_calculated_time($qubaids) {
+ global $DB;
+
+ $timemodified = time() - self::TIME_TO_CACHE;
+ return $DB->get_field_select('question_statistics', 'timemodified', 'hashcode = ? AND timemodified > ?',
+ array($qubaids->get_hash_code(), $timemodified));
+ }
+
+ /** @var integer Time after which statistics are automatically recomputed. */
+ const TIME_TO_CACHE = 900; // 15 minutes.
+
+ /**
+ * Used when computing Coefficient of Internal Consistency by quiz statistics.
+ *
+ * @return float
+ */
+ public function get_sum_of_mark_variance() {
+ return $this->sumofmarkvariance;
+ }
+
+ /**
+ * @param $qubaids \qubaid_condition
+ * @return array with three items
+ * - $lateststeps array of latest step data for the question usages
+ * - $summarks array of total marks for each usage, indexed by usage id
+ * - $summarksavg the average of the total marks over all the usages
+ */
+ protected function get_latest_steps($qubaids) {
+ $dm = new \question_engine_data_mapper();
+
+ $fields = " qas.id,
+ qa.questionusageid,
+ qa.questionid,
+ qa.slot,
+ qa.maxmark,
+ qas.fraction * qa.maxmark as mark";
+
+ $lateststeps = $dm->load_questions_usages_latest_steps($qubaids, array_keys($this->questionstats), $fields);
+ $summarks = array();
+ if ($lateststeps) {
+ foreach ($lateststeps as $step) {
+ if (!isset($summarks[$step->questionusageid])) {
+ $summarks[$step->questionusageid] = 0;
+ }
+ $summarks[$step->questionusageid] += $step->mark;
+ }
+ $summarksavg = array_sum($summarks) / count($summarks);
+ } else {
+ $summarksavg = null;
}
+ return array($lateststeps, $summarks, $summarksavg);
}
/**
* Update $stats->totalmarks, $stats->markarray, $stats->totalothermarks
* and $stats->othermarksarray to include another state.
*
- * @param object $step the state to add to the statistics.
- * @param object $stats the question statistics we are accumulating.
- * @param array $summarks of the sum of marks for each question usage, indexed by question usage id
- * @param bool $positionstat whether this is a statistic of position of question.
+ * @param object $step the state to add to the statistics.
+ * @param calculated $stats the question statistics we are accumulating.
+ * @param array $summarks of the sum of marks for each question usage, indexed by question usage id
+ * @param bool $positionstat whether this is a statistic of position of question.
*/
protected function initial_steps_walker($step, $stats, $summarks, $positionstat = true) {
$stats->s++;
* Perform some computations on the per-question statistics calculations after
* we have been through all the states.
*
- * @param object $stats quetsion stats to update.
+ * @param calculated $stats question stats to update.
*/
protected function initial_question_walker($stats) {
$stats->markaverage = $stats->totalmarks / $stats->s;
* Now we know the averages, accumulate the date needed to compute the higher
* moments of the question scores.
*
- * @param object $step the state to add to the statistics.
- * @param object $stats the question statistics we are accumulating.
- * @param array $summarks of the sum of marks for each question usage, indexed by question usage id
+ * @param object $step the state to add to the statistics.
+ * @param calculated $stats the question statistics we are accumulating.
+ * @param array $summarks of the sum of marks for each question usage, indexed by question usage id
* @param float $summarksavg the average sum of marks for all question usages
*/
protected function secondary_steps_walker($step, $stats, $summarks, $summarksavg) {
if ($stats->subquestion) {
$othermarkdifference = $summarks[$step->questionusageid] - $stats->othermarkaverage;
} else {
- $othermarkdifference = $summarks[$step->questionusageid] - $step->mark -
- $stats->othermarkaverage;
+ $othermarkdifference = $summarks[$step->questionusageid] - $step->mark - $stats->othermarkaverage;
}
$overallmarkdifference = $summarks[$step->questionusageid] - $summarksavg;
$sortedmarkdifference = array_shift($stats->markarray) - $stats->markaverage;
- $sortedothermarkdifference = array_shift($stats->othermarksarray) -
- $stats->othermarkaverage;
+ $sortedothermarkdifference = array_shift($stats->othermarksarray) - $stats->othermarkaverage;
$stats->markvariancesum += pow($markdifference, 2);
$stats->othermarkvariancesum += pow($othermarkdifference, 2);
/**
* Perform more per-question statistics calculations.
*
- * @param object $stats quetsion stats to update.
+ * @param calculated $stats question stats to update.
*/
protected function secondary_question_walker($stats) {
+
if ($stats->s > 1) {
$stats->markvariance = $stats->markvariancesum / ($stats->s - 1);
$stats->othermarkvariance = $stats->othermarkvariancesum / ($stats->s - 1);
$stats->covariance = $stats->covariancesum / ($stats->s - 1);
$stats->covariancemax = $stats->covariancemaxsum / ($stats->s - 1);
$stats->covariancewithoverallmark = $stats->covariancewithoverallmarksum /
- ($stats->s - 1);
+ ($stats->s - 1);
$stats->sd = sqrt($stats->markvariancesum / ($stats->s - 1));
+ if ($stats->covariancewithoverallmark >= 0) {
+ $stats->negcovar = 0;
+ } else {
+ $stats->negcovar = 1;
+ }
} else {
$stats->markvariance = null;
$stats->othermarkvariance = null;
$stats->covariancemax = null;
$stats->covariancewithoverallmark = null;
$stats->sd = null;
+ $stats->negcovar = 0;
}
+
+
if ($stats->markvariance * $stats->othermarkvariance) {
$stats->discriminationindex = 100 * $stats->covariance /
- sqrt($stats->markvariance * $stats->othermarkvariance);
+ sqrt($stats->markvariance * $stats->othermarkvariance);
} else {
$stats->discriminationindex = null;
}
if ($stats->covariancemax) {
$stats->discriminativeefficiency = 100 * $stats->covariance /
- $stats->covariancemax;
+ $stats->covariancemax;
} else {
$stats->discriminativeefficiency = null;
}
* @return number the random guess score for this question.
*/
protected function get_random_guess_score($questiondata) {
- return question_bank::get_qtype(
- $questiondata->qtype, false)->get_random_guess_score($questiondata);
- }
-
- /**
- * Used when computing CIC.
- * @return number
- */
- public function get_sum_of_mark_variance() {
- return $this->sumofmarkvariance;
+ return \question_bank::get_qtype(
+ $questiondata->qtype, false)->get_random_guess_score($questiondata);
}
/**
- * @param qubaid_condition $qubaids
+ * @param $qubaids \qubaid_condition
*/
- public function get_cached($qubaids) {
- global $DB;
- $questionstats = $DB->get_records('question_statistics',
- array('hashcode' => $qubaids->get_hash_code()));
-
- $subquestionstats = array();
- foreach ($questionstats as $stat) {
- if ($stat->slot) {
- $this->questions[$stat->slot]->_stats = $stat;
- } else {
- $subquestionstats[$stat->questionid] = $stat;
- }
+ protected function cache_stats($qubaids) {
+ foreach ($this->questionstats as $questionstat) {
+ $questionstat->cache($qubaids);
}
- if (!empty($subquestionstats)) {
- $subqstofetch = array_keys($subquestionstats);
- $this->subquestions = question_load_questions($subqstofetch);
- foreach ($this->subquestions as $subqid => $subq) {
- $this->subquestions[$subqid]->_stats = $subquestionstats[$subqid];
- $this->subquestions[$subqid]->maxmark = $subq->defaultmark;
- }
+ foreach ($this->subquestionstats as $subquestionstat) {
+ $subquestionstat->cache($qubaids);
}
}
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
-
+namespace core_question\statistics\responses;
defined('MOODLE_INTERNAL') || die();
-
/**
* This class can store and compute the analysis of the responses to a particular
* question.
* @author Jamie Pratt <me@jamiep.org>
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
-class question_response_analyser {
+class analyser {
/** @var object the data from the database that defines the question. */
protected $questiondata;
public function __construct($questiondata) {
$this->questiondata = $questiondata;
- $this->responseclasses =
- question_bank::get_qtype($questiondata->qtype)->get_possible_responses(
- $questiondata);
+ $this->responseclasses = \question_bank::get_qtype($questiondata->qtype)->get_possible_responses($questiondata);
foreach ($this->responseclasses as $subpartid => $responseclasses) {
foreach ($responseclasses as $responseclassid => $notused) {
$this->responses[$subpartid][$responseclassid] = array();
/**
* Analyse all the response data for for all the specified attempts at
* this question.
- * @param qubaid_condition $qubaids which attempts to consider.
+ * @param \qubaid_condition $qubaids which attempts to consider.
*/
public function calculate($qubaids) {
// Load data.
- $dm = new question_engine_data_mapper();
+ $dm = new \question_engine_data_mapper();
$questionattempts = $dm->load_attempts_at_question($this->questiondata->id, $qubaids);
// Analyse it.
/**
* Analyse the data from one question attempt.
- * @param question_attempt $qa the data to analyse.
+ * @param \question_attempt $qa the data to analyse.
*/
- protected function add_data_from_one_attempt(question_attempt $qa) {
- $blankresponse = question_classified_response::no_response();
+ protected function add_data_from_one_attempt(\question_attempt $qa) {
+ $blankresponse = \question_classified_response::no_response();
$partresponses = $qa->classify_response();
foreach ($partresponses as $subpartid => $partresponse) {
if (!isset($this->responses[$subpartid][$partresponse->responseclassid]
[$partresponse->response])) {
- $resp = new stdClass();
+ $resp = new \stdClass();
$resp->count = 0;
if (!is_null($partresponse->fraction)) {
$resp->fraction = $partresponse->fraction;
/**
* Store the computed response analysis in the question_response_analysis table.
- * @param qubaid_condition $qubaids
+ * @param \qubaid_condition $qubaids
* data corresponding to.
* @return bool true if cached data was found in the database and loaded, otherwise false, to mean no data was loaded.
*/
}
foreach ($rows as $row) {
- $this->responses[$row->subqid][$row->aid][$row->response] = new stdClass();
+ $this->responses[$row->subqid][$row->aid][$row->response] = new \stdClass();
$this->responses[$row->subqid][$row->aid][$row->response]->count = $row->rcount;
$this->responses[$row->subqid][$row->aid][$row->response]->fraction = $row->credit;
}
/**
* Store the computed response analysis in the question_response_analysis table.
- * @param qubaid_condition $qubaids
+ * @param \qubaid_condition $qubaids
*/
public function store_cached($qubaids) {
global $DB;
foreach ($this->responses as $subpartid => $partdata) {
foreach ($partdata as $responseclassid => $classdata) {
foreach ($classdata as $response => $data) {
- $row = new stdClass();
+ $row = new \stdClass();
$row->hashcode = $qubaids->get_hash_code();
$row->questionid = $this->questiondata->id;
$row->subqid = $subpartid;
