mirror of
https://github.com/moodle/moodle.git
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222 lines
7.8 KiB
PHP
222 lines
7.8 KiB
PHP
<?php
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// This file is part of Moodle - http://moodle.org/
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//
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// Moodle is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// Moodle is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
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namespace qbank_statistics;
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use core_question\statistics\questions\all_calculated_for_qubaid_condition;
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use quiz_statistics_report;
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defined('MOODLE_INTERNAL') || die();
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require_once($CFG->dirroot . '/mod/quiz/report/statistics/statisticslib.php');
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require_once($CFG->dirroot . '/mod/quiz/report/default.php');
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require_once($CFG->dirroot . '/mod/quiz/report/statistics/report.php');
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require_once($CFG->dirroot . '/mod/quiz/report/reportlib.php');
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require_once($CFG->dirroot . '/mod/quiz/attemptlib.php');
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/**
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* Helper for statistics
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*
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* @package qbank_statistics
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* @copyright 2021 Catalyst IT Australia Pty Ltd
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* @author Nathan Nguyen <nathannguyen@catalyst-au.net>
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* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
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*/
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class helper {
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/**
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* @var float Threshold to determine 'Needs checking?'
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*/
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private const NEED_FOR_REVISION_LOWER_THRESHOLD = 30;
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/**
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* @var float Threshold to determine 'Needs checking?'
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*/
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private const NEED_FOR_REVISION_UPPER_THRESHOLD = 50;
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/**
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* Return ids of all quizzes that use the question
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*
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* @param int $questionid id of the question
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* @return array list of quizids
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* @throws \dml_exception
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*/
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public static function get_quizzes(int $questionid): array {
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global $DB;
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$quizzes = $DB->get_fieldset_sql("
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SELECT DISTINCT qa.quiz as id
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FROM {quiz_attempts} qa
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JOIN {question_usages} qu ON qu.id = qa.uniqueid
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JOIN {question_attempts} qatt ON qatt.questionusageid = qu.id
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WHERE qatt.questionid = :questionid",
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['questionid' => $questionid]
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);
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return $quizzes;
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}
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/**
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* Load question stats from a quiz
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*
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* @param int $quizid quiz object or its id
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* @return all_calculated_for_qubaid_condition
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*/
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private static function load_question_stats(int $quizid): all_calculated_for_qubaid_condition {
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// Turn to quiz object.
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$quiz = new \stdClass();
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$quiz->id = $quizid;
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// All questions, no groups.
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$report = new quiz_statistics_report();
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$questions = $report->load_and_initialise_questions_for_calculations($quiz);
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$qubaids = quiz_statistics_qubaids_condition($quiz->id, new \core\dml\sql_join());
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$progress = new \core\progress\none();
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$qcalc = new \core_question\statistics\questions\calculator($questions, $progress);
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$quizcalc = new \quiz_statistics\calculator($progress);
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if ($quizcalc->get_last_calculated_time($qubaids) === false) {
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$questionstats = $qcalc->calculate($qubaids);
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} else {
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$questionstats = $qcalc->get_cached($qubaids);
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}
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return $questionstats;
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}
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/**
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* Load a specified stats item for a question
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*
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* @param int $quizid quiz id
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* @param int $questionid question id
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* @param string $item a stats item
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* @return float|int
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*/
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public static function load_question_stats_item(int $quizid, int $questionid, string $item): ?float {
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$questionstats = self::load_question_stats($quizid);
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// Find in main question.
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foreach ($questionstats->questionstats as $stats) {
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if ($stats->questionid == $questionid && isset($stats->$item)) {
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return $stats->$item;
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}
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}
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// If not found, find in sub questions.
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foreach ($questionstats->subquestionstats as $stats) {
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if ($stats->questionid == $questionid && isset($stats->$item)) {
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return $stats->$item;
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}
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}
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return null;
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}
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/**
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* Calculate average for a stats item on a question.
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*
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* @param int $questionid id of the question
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* @param string $item stats item
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* @return float|null
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*/
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private static function calculate_average_question_stats_item(int $questionid, string $item): ?float {
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$quizzes = self::get_quizzes($questionid);
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$sum = 0;
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$quizcount = count($quizzes);
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foreach ($quizzes as $quizid) {
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$value = self::load_question_stats_item($quizid, $questionid, $item);
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if (!is_null($value)) {
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$sum += $value;
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} else {
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// Exclude this value when it is null.
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$quizcount--;
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}
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}
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// Return null if there is no quizzes.
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if (empty($quizcount)) {
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return null;
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}
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// Average value per quiz.
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$average = $sum / $quizcount;
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return $average;
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}
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/**
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* Calculate average facility index
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*
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* @param int $questionid
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* @return float|null
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*/
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public static function calculate_average_question_facility(int $questionid): ?float {
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return self::calculate_average_question_stats_item($questionid, 'facility');
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}
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/**
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* Calculate average discriminative efficiency
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*
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* @param int $questionid question id
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* @return float|null
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*/
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public static function calculate_average_question_discriminative_efficiency(int $questionid): ?float {
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return self::calculate_average_question_stats_item($questionid, 'discriminativeefficiency');
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}
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/**
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* Calculate average discriminative efficiency
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*
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* @param int $questionid question id
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* @return float|null
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*/
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public static function calculate_average_question_discrimination_index(int $questionid): ?float {
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return self::calculate_average_question_stats_item($questionid, 'discriminationindex');
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}
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/**
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* Format a number to a localised percentage with specified decimal points.
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*
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* @param float|null $number The number being formatted
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* @param bool $fraction An indicator for whether the number is a fraction or is already multiplied by 100
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* @param int $decimals Sets the number of decimal points
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* @return string
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* @throws \coding_exception
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*/
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public static function format_percentage(?float $number, bool $fraction = true, int $decimals = 2): string {
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if (is_null($number)) {
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return get_string('na', 'qbank_statistics');
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}
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$coefficient = $fraction ? 100 : 1;
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return get_string('percents', 'moodle', format_float($number * $coefficient, $decimals));
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}
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/**
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* Format discrimination index (Needs checking?).
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*
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* @param float|null $value stats value
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* @return array
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*/
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public static function format_discrimination_index(?float $value): array {
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if (is_null($value)) {
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$content = get_string('emptyvalue', 'qbank_statistics');
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$classes = '';
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} else if ($value < self::NEED_FOR_REVISION_LOWER_THRESHOLD) {
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$content = get_string('verylikely', 'qbank_statistics');
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$classes = 'alert-danger';
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} else if ($value < self::NEED_FOR_REVISION_UPPER_THRESHOLD) {
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$content = get_string('likely', 'qbank_statistics');
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$classes = 'alert-warning';
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} else {
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$content = get_string('unlikely', 'qbank_statistics');
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$classes = 'alert-success';
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}
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return [$content, $classes];
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}
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}
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