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MDL-14203 "split report into two seperate reports - Quiz Statistics report and Individual Item Analysis report" added CIC, ER and SE calculations. Calculation needs debugging.

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This commit is contained in:
jamiesensei
2008-06-10 18:15:19 +00:00
parent 0c1c764e82
commit 08a7ead5d1
2 changed files with 66 additions and 20 deletions
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lang/en_utf8/quiz_statistics.php
+5 -1
View File
@@ -19,9 +19,13 @@ $string['allattemptsavg'] = 'Average grade of all attempts';
$string['attemptsall'] = 'all attempts';
$string['attemptsfirst'] = 'first attempt';
$string['errormedian'] = 'Error fetching median';
$string['errorpowers'] = 'Error fetching powers';
$string['errorpowers'] = 'Error fetching data to calculate variance for quiz grades';
$string['errorpowerquestions'] = 'Error fetching data to calculate variance for question grades';
$string['median'] = 'Median grade';
$string['standarddeviation'] = 'Standard deviation';
$string['skewness'] = 'Score distribution skewness';
$string['kurtosis'] = 'Score distribution kurtosis';
$string['cic'] = 'Coefficient of internal consistency';
$string['errorratio'] = 'Error ratio';
$string['standarderror'] = 'Standard error';
?>
mod/quiz/report/statistics/report.php
+61 -19
View File
@@ -101,13 +101,14 @@ class quiz_report extends quiz_default_report {
$mform->set_data(array('useallattempts' => $useallattempts));
$mform->display();
}
$fromqa = '{quiz_attempts} qa ';
$whereqa = 'quiz = ? AND preview=0 AND timefinish !=0 ';
$sql = 'SELECT (attempt=1) AS isfirst, COUNT(1) AS countrecs, SUM(sumgrades) AS total ' .
'FROM {quiz_attempts} ' .
'WHERE quiz = :quiz AND preview=0 AND timefinish !=0 ' .
'FROM '.$fromqa.
'WHERE ' .$whereqa.
'GROUP BY (attempt=1)';
if (!$attempttotals = $DB->get_records_sql($sql, array('quiz' => $quiz->id))){
if (!$attempttotals = $DB->get_records_sql($sql, array($quiz->id))){
print_heading(get_string('noattempts','quiz'));
return true;
} else {
@@ -133,8 +134,6 @@ class quiz_report extends quiz_default_report {
print_table($quizoverallstatistics);
}
//get the median
if (!$table->is_downloading()) {
if ($useallattempts){
$usingattempts = $allattempts;
@@ -143,7 +142,7 @@ class quiz_report extends quiz_default_report {
} else {
$usingattempts = $firstattempt;
$usingattempts->heading = get_string('statsforfirstattempts', 'quiz_statistics');
$usingattempts->sql = 'AND attempt=1 ';
$usingattempts->sql = 'AND qa.attempt=1 ';
}
print_heading($usingattempts->heading);
if (($usingattempts->countrecs/2)==floor($usingattempts->countrecs/2)){
@@ -155,11 +154,11 @@ class quiz_report extends quiz_default_report {
$limit = 1;
}
$sql = 'SELECT id, sumgrades ' .
'FROM {quiz_attempts} ' .
'WHERE quiz = :quiz AND preview=0 AND timefinish !=0 ' .
'FROM ' .$fromqa.
'WHERE ' .$whereqa.
$usingattempts->sql.
'ORDER BY sumgrades';
if (!$mediangrades = $DB->get_records_sql_menu($sql, array('quiz' => $quiz->id), $limitoffset, $limit)){
if (!$mediangrades = $DB->get_records_sql_menu($sql, array($quiz->id), $limitoffset, $limit)){
print_error('errormedian', 'quiz_statistics');
}
if (count($mediangrades)==1){
@@ -173,13 +172,12 @@ class quiz_report extends quiz_default_report {
//differences between grades and mean grade
$mean = $usingattempts->total / $usingattempts->countrecs;
$sql = "SELECT " .
"SUM(POWER((sumgrades - ?),2)) AS power2, " .
"SUM(POWER((sumgrades - ?),3)) AS power3, ".
"SUM(POWER((sumgrades - ?),4)) AS power4 ".
"FROM {quiz_attempts} " .
"WHERE quiz = ? AND preview=0 AND timefinish !=0 " .
$usingattempts->sql.
"ORDER BY sumgrades";
"SUM(POWER((qa.sumgrades - ?),2)) AS power2, " .
"SUM(POWER((qa.sumgrades - ?),3)) AS power3, ".
"SUM(POWER((qa.sumgrades - ?),4)) AS power4 ".
'FROM ' .$fromqa.
'WHERE ' .$whereqa.
$usingattempts->sql;
$params = array($mean, $mean, $mean, $quiz->id);
if (!$powers = $DB->get_record_sql($sql, $params)){
print_error('errorpowers', 'quiz_statistics');
@@ -211,9 +209,53 @@ class quiz_report extends quiz_default_report {
$quizattsstatistics->data[] = array(get_string('standarddeviation', 'quiz_statistics'), quiz_report_scale_sumgrades_as_percentage($sd, $quiz));
$quizattsstatistics->data[] = array(get_string('skewness', 'quiz_statistics'), $skewness);
$quizattsstatistics->data[] = array(get_string('kurtosis', 'quiz_statistics'), $kurtosis);
print_table($quizattsstatistics);
}
$qgradeavgsql = "SELECT qs.question, AVG(qs.grade) FROM " .
"{question_sessions} qns, " .
"{question_states} qs, " .
"{question} q, " .
$fromqa.' '.
'WHERE ' .$whereqa.
'AND qns.attemptid = qa.uniqueid '.
'AND qs.question = q.id ' .
'AND q.length > 0 '.
$usingattempts->sql.
'AND qns.newgraded = qs.id GROUP BY qs.question';
$qgradeavgs = $DB->get_records_sql_menu($qgradeavgsql, array($quiz->id));
$sum = 0;
foreach ($qgradeavgs as $qid => $qgradeavg){
$sql = 'SELECT ' .
'SUM(POWER((qs.grade - ?),2)) AS power2 ' .
'FROM ' .
'{question_sessions} qns, ' .
'{question_states} qs, ' .
'{question} q, ' .
$fromqa.' '.
'WHERE ' .$whereqa.
'AND qns.attemptid = qa.uniqueid '.
'AND qs.question = ? ' .
$usingattempts->sql.
'AND qns.newgraded = qs.id';
$params = array($qgradeavg, $quiz->id, $qid);
$power = $DB->get_field_sql($sql, $params);
if ($power === false){
print_error('errorpowerquestions', 'quiz_statistics');
}
$sum += $power;
}
$sumofvarianceforallpositions = $sum / ($usingattempts->countrecs -1);
$p = count($qgradeavgs);//no of positions
$cic = (100 * $p / ($p -1)) * (1 - ($sumofvarianceforallpositions/$k2));
$quizattsstatistics->data[] = array(get_string('cic', 'quiz_statistics'), number_format($cic, $quiz->decimalpoints).' %');
$errorratio = 100 * sqrt(1-($cic/100));
$quizattsstatistics->data[] = array(get_string('errorratio', 'quiz_statistics'), number_format($errorratio, $quiz->decimalpoints).' %');
$standarderror = ($errorratio * $sd / 100);
$quizattsstatistics->data[] = array(get_string('standarderror', 'quiz_statistics'),
quiz_report_scale_sumgrades_as_percentage($standarderror, $quiz));
print_table($quizattsstatistics);
}
return true;
}