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MDL-15268 "Content for Quiz Statistics report table" know looping through all question grades fetched from the db to calculate position statistics.

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jamiesensei 2008-07-16 11:55:38 +00:00
parent 9faa5c4469
commit ea751786e0
3 changed files with 139 additions and 8 deletions
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6
lang/en_utf8/quiz_statistics.php
View File

@ -24,6 +24,7 @@ $string['attemptsfirst'] = 'first attempt';
$string['errormedian'] = 'Error fetching median';
$string['errorpowers'] = 'Error fetching data to calculate variance for quiz grades';
$string['errorpowerquestions'] = 'Error fetching data to calculate variance for question grades';
$string['errorstatisticsquestions'] = 'Error fetching data to calculate statistics for question grades';
$string['median'] = 'Median grade';
$string['standarddeviation'] = 'Standard deviation';
$string['skewness'] = 'Score distribution skewness';
@ -34,8 +35,11 @@ $string['standarderror'] = 'Standard error';
$string['questionnumber'] = 'Q#';
$string['quizstructureanalysis'] = 'Quiz structure analysis';
$string['questiontype'] = 'Q type';
$string['intended_weight'] = 'Intended question weight';
$string['intended_weight'] = 'Intended weight';
$string['random_guess_score'] = 'Random guess score';
$string['facility'] = 'Facility index';
$string['nostudentsingroup'] = 'There are no students in this group yet';
$string['discrimination_index'] = 'Discrimination Index';
$string['discriminative_efficiency'] = 'Discriminative Efficiency';
$string['effective_weight'] = 'Effective weight';
?>

115
mod/quiz/report/statistics/report.php
View File

@ -144,6 +144,7 @@ class quiz_statistics_report extends quiz_default_report {
}
$usingattempts->heading = get_string('statsfor', 'quiz_statistics', $usingattempts->attempts);
$s = $usingattempts->countrecs;
$sumgradesavg = $usingattempts->total / $usingattempts->countrecs;
}
} else {
$s = 0;
@ -243,11 +244,14 @@ class quiz_statistics_report extends quiz_default_report {
}
}
if ($s){
//CIC, ER and SE.
/* //CIC, ER and SE.
//http://docs.moodle.org/en/Development:Quiz_item_analysis_calculations_in_practise#CIC.2C_ER_and_SE
list($qsql, $sqlparams) = $DB->get_in_or_equal(array_keys($questions), SQL_PARAMS_NAMED);
$sqlparams += $qaparams;//put quiz id in at beginning of array
$qgradeavgsql = "SELECT qs.question, AVG(qs.grade) FROM " .
$qgradeavgsql = "SELECT qs.question, " .
"AVG(qs.grade) AS gradeaverage " .
"AVG(qa.sumgrades - qs.grade) AS sumgradeaverage " .
"FROM " .
"{question_sessions} qns, " .
"{question_states} qs, " .
$fromqa.' '.
@ -256,7 +260,7 @@ class quiz_statistics_report extends quiz_default_report {
'AND qs.question '.$qsql.' ' .
$usingattempts->sql.
'AND qns.newgraded = qs.id GROUP BY qs.question';
$qgradeavgs = $DB->get_records_sql_menu($qgradeavgsql, $sqlparams);
$qgradeavgs = $DB->get_records_sql($qgradeavgsql, $sqlparams);
$sum = 0;
$sql = 'SELECT COUNT(1) as s,' .
@ -283,13 +287,112 @@ class quiz_statistics_report extends quiz_default_report {
}
$sum += $fromdb->power2;
}
//Discrimination index
$sql = 'SELECT qs.id, ' .
'qs.question, ' .
'qa.sumgrades - qs.grade AS sum, ' .
'qs.grade ' .
'FROM ' .
'{question_sessions} qns, ' .
'{question_states} qs, '.
$fromqa.' '.
'WHERE ' .$whereqa.
'AND qns.attemptid = qa.uniqueid '.
$usingattempts->sql.
'AND qns.newgraded = qs.id';
$fromdbrs = $DB->get_recordset_sql($sql, $qaparams);
if ($fromdbrs === false){
print_error('errorpowerquestions', 'quiz_statistics');
}
foreach ($fromdbrs as $record){
}*/
$sql = 'SELECT qs.id, ' .
'qs.question, ' .
'qa.sumgrades, ' .
'qs.grade ' .
'FROM ' .
'{question_sessions} qns, ' .
'{question_states} qs, '.
$fromqa.' '.
'WHERE ' .$whereqa.
'AND qns.attemptid = qa.uniqueid '.
$usingattempts->sql.
'AND qns.newgraded = qs.id';
$fromdbrs = $DB->get_recordset_sql($sql, $qaparams);
if ($fromdbrs === false){
print_error('errorstatisticsquestions', 'quiz_statistics');
}
foreach (array_keys($questions) as $qid){
$questions[$qid]->s = 0;
$questions[$qid]->totalgrades = 0;
$questions[$qid]->totalothergrades = 0;
$questions[$qid]->gradevariancesum = 0;
$questions[$qid]->othergradevariancesum = 0;
$questions[$qid]->covariancesum = 0;
$questions[$qid]->covariancemaxsum = 0;
$questions[$qid]->covariancewithoverallgradesum = 0;
$questions[$qid]->gradearray = array();
$questions[$qid]->othergradesarray = array();
}
foreach ($fromdbrs as $record){
$questions[$record->question]->s++;
$questions[$record->question]->totalgrades += $record->grade;
$questions[$record->question]->totalothergrades += $record->sumgrades - $record->grade;
//need to sort these to calculate max covariance :
$questions[$record->question]->gradearray[] = $record->grade;
$questions[$record->question]->othergradesarray[] = $record->sumgrades - $record->grade;
}
foreach (array_keys($questions) as $qid){
$questions[$qid]->gradeaverage = $questions[$qid]->totalgrades / $s;
$questions[$qid]->facility = $questions[$qid]->gradeaverage / $questions[$qid]->grade;
$questions[$qid]->othergradeaverage = $questions[$qid]->totalothergrades / $s;
sort($questions[$qid]->gradearray, SORT_NUMERIC);
sort($questions[$qid]->othergradesarray, SORT_NUMERIC);
}
//go through the records one more time
foreach ($fromdbrs as $record){
$gradedifference = ($record->grade - $questions[$record->question]->gradeaverage);
$othergradedifference = (($record->sumgrades - $record->grade) - $questions[$record->question]->othergradeaverage);
$overallgradedifference = $record->sumgrades - $sumgradesavg;
$sortedgradedifference = (array_shift($questions[$qid]->gradearray) - $questions[$record->question]->gradeaverage);
$sortedothergradedifference = (array_shift($questions[$qid]->othergradesarray) - $questions[$record->question]->othergradeaverage);
$questions[$record->question]->gradevariancesum += pow($gradedifference,2);
$questions[$record->question]->othergradevariancesum += pow($othergradedifference,2);
$questions[$record->question]->covariancesum += $gradedifference * $othergradedifference;
$questions[$record->question]->covariancemaxsum += $sortedgradedifference * $sortedothergradedifference;
$questions[$record->question]->covariancewithoverallgradesum += $gradedifference * $overallgradedifference;
}
$sumofcovariancewithoverallgrade = 0;
$sumofgradevariance =0;
foreach (array_keys($questions) as $qid){
$questions[$qid]->gradevariance = $questions[$qid]->gradevariancesum / ($s -1);
$questions[$qid]->othergradevariance = $questions[$qid]->othergradevariancesum / ($s -1);
$questions[$qid]->covariance = $questions[$qid]->covariancesum / ($s -1);
$questions[$qid]->covariancemax = $questions[$qid]->covariancemaxsum / ($s -1);
$sumofgradevariance += $questions[$qid]->gradevariance;
$questions[$qid]->covariancewithoverallgrade = $questions[$qid]->covariancewithoverallgradesum / ($s-1);
$sumofcovariancewithoverallgrade += sqrt($questions[$qid]->covariancewithoverallgrade);
$questions[$qid]->sd = sqrt($questions[$qid]->gradevariancesum / ($s -1));
//avoid divide by zero
if (sqrt($questions[$qid]->gradevariance * $questions[$qid]->othergradevariance)){
$questions[$qid]->discriminationindex = 100*$questions[$qid]->covariance
/ sqrt($questions[$qid]->gradevariance * $questions[$qid]->othergradevariance);
} else {
$questions[$qid]->discriminationindex = '';
}
$questions[$qid]->discriminativeefficiency = 100*$questions[$qid]->covariance / $questions[$qid]->covariancemax;
}
foreach (array_keys($questions) as $qid){
$questions[$qid]->effectiveweight = 100 * sqrt($questions[$qid]->covariancewithoverallgrade)/$sumofcovariancewithoverallgrade;
}
}
if (!$table->is_downloading()){
if ($s>1){
$sumofvarianceforallpositions = $sum / ($s -1);
$p = count($qgradeavgs);//no of positions
$p = count($questions);//no of positions
if ($p > 1){
$cic = (100 * $p / ($p -1)) * (1 - ($sumofvarianceforallpositions/$k2));
$cic = (100 * $p / ($p -1)) * (1 - ($sumofgradevariance)/$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).' %');

26
mod/quiz/report/statistics/statistics_table.php
View File

@ -51,6 +51,15 @@ class quiz_report_statistics_table extends flexible_table {
$columns[]= 'intended_weight';
$headers[]= get_string('intended_weight', 'quiz_statistics');
$columns[]= 'effective_weight';
$headers[]= get_string('effective_weight', 'quiz_statistics');
$columns[]= 'discrimination_index';
$headers[]= get_string('discrimination_index', 'quiz_statistics');
$columns[]= 'discriminative_efficiency';
$headers[]= get_string('discriminative_efficiency', 'quiz_statistics');
$this->define_columns($columns);
$this->define_headers($headers);
$this->sortable(false);
@ -58,8 +67,11 @@ class quiz_report_statistics_table extends flexible_table {
$this->column_class('s', 'numcol');
$this->column_class('random_guess_score', 'numcol');
$this->column_class('intended_weight', 'numcol');
$this->column_class('effective_weight', 'numcol');
$this->column_class('sd', 'numcol');
$this->column_class('facility', 'numcol');
$this->column_class('discrimination_index', 'numcol');
$this->column_class('discriminative_efficiency', 'numcol');
// Set up the table
$this->define_baseurl($reporturl->out());
@ -107,7 +119,19 @@ class quiz_report_statistics_table extends flexible_table {
function col_intended_weight($question){
return quiz_report_scale_sumgrades_as_percentage($question->grade, $this->quiz);
}
function col_effective_weight($question){
return number_format($question->effectiveweight, 2).' %';
}
function col_discrimination_index($question){
if (is_numeric($question->discriminationindex)){
return number_format($question->discriminationindex, 2).' %';
} else {
return $question->discriminationindex;
}
}
function col_discriminative_efficiency($question){
return number_format($question->discriminativeefficiency, 2).' %';
}
function col_random_guess_score($question){
$randomguessscore = question_get_random_guess_score($question);
if (is_numeric($randomguessscore)){