diff --git a/local/stats/amcstats b/local/stats/amcstats
index 16d046d..7bf8ebe 100755
--- a/local/stats/amcstats
+++ b/local/stats/amcstats
@@ -1,59 +1,165 @@
 #!/usr/bin/env php
 <?php
 
 require_once(dirname(__FILE__).'/lib/lib_amcstats.php');
 
 $shortopts = '';
 $shortopts .= 'h';
 
 $longopts = array(
 	'help',
 	'csv:',
+	'sample:',
+	'type:',
 	);
 
 $options = getopt($shortopts, $longopts);
 
 if (empty($options) or array_key_exists('h', $options) or array_key_exists('help', $options)) {
 	echo "USAGE: ".basename(__FILE__)." [parameters (see below)]
 
-\tDo statistics:
-\t\t-f|--csv filename[;filename]\n\n";
+\tStats on AMC export files:
+\t\t-f|--csv filename[;filename] --sample global,profs,sections --type average,dist,dist_percentage,questions,marks\n\n";
 echo "\tHelp:
 \t\t-h|--help\n\n";
 	echo "\n";
 	echo "e.g.: ".basename(__FILE__)." -h\n";
-	echo "e.g.: ".basename(__FILE__)." --csv tournesol.csv@80@tournesol,favre.csv@79@favre\n";
+	echo "e.g.: ".basename(__FILE__)." --csv tournesol/tournesol.csv/30,favre/favre.csv/29 --sample global --type general\n";
 	exit;
 }
 
 if (!empty($options['csv'])) $csv = $options['csv'];
-
-$files = array_unique(explode(',', $csv));
-
-$EC = new ExamCalcs();
-
-foreach($files as $file_info) {
-	$details = explode('@', $file_info);
-	$filename = $details[0];
-	if (array_key_exists(1, $details)) { $name = $details[1]; } else { $name = preg_replace('/\..*$/', '', $filename); }
-	if (array_key_exists(2, $details)) { $total = $details[2]; } else { $total = null; }
-
-	echo "NAME: $name, FILE: $filename, TOTAL: $total\n";
+if (!empty($options['sample'])) $samples = explode(',', $options['sample']); else $samples = array( 'global');
+if (!empty($options['type'])) $types = explode(',', $options['type']); else $types = array( 'average' );
+
+// Create ExamCalcs object
+$Global = new ExamCalcs();
+
+// Load files
+$loaded = array();
+foreach(explode(',', $csv) as $file_info) {
+	$details = explode('/', $file_info);
+	if (count($details) < 3 ) {
+		echo "CSV file list should look like: tournesol/tournesol.csv/30[,favre@favre.csv@29,...]\n";
+		exit;
+	}
+	$name = $details[0];
+	$filename = $details[1];
+	$total = $details[2];
 
 	if(!is_file($filename)) {
 		echo "File not found: $filename\n";
 		exit;
 	}
 
-	$EC->addFile($name, $filename, $total);
+	if (in_array($filename, $loaded)) {
+		echo "Trying to load $filename a second time...\n";
+		exit;
+	}
+	$Global->addFile($name, $filename, $total);
+	$loaded[] = $filename;
 }
 
-$sorted_data = $EC->sortByTotalPoints(false);
-print_r($EC->getTeachers());
-print_r($EC->getSections());
-$EC->doStatsOnCommonItems(false);
-$EC->doStats();
+foreach ($types as $type) {
+
+	// Build samples
+	foreach ($samples as $sample) {
+		// Print header
+		$sample_header = strtoupper($sample);
+		switch ($type) {
+			case 'average':
+				printAverage($sample_header);
+				break;
+			case 'dist':
+			case 'dist_percentage':
+				printDistribution($sample_header);
+				break;
+			case 'marks':
+				break;
+		}
+
+		// Build samples
+		$Samples = array();
+		switch ($sample) {
+			case 'global':
+				$Samples['global'] = new ExamCalcs($Global->getDataSet());
+				break;
+			case 'sections':
+				foreach ($Global->getSections() as $section) {
+					$tmpSample = new ExamCalcs($Global->getDataSet());
+					$tmpSample->filterBySections($section);
+					$Samples[$section] = $tmpSample;
+				}
+				break;
+			case 'profs':
+				foreach ($Global->getTeachers() as $prof) {
+					$tmpSample = new ExamCalcs($Global->getDataSet());
+					$tmpSample->filterByTeachers($prof);
+					$Samples[$prof] = $tmpSample;
+				}
+				break;
+		}
+
+		// Print stats
+		foreach ($Samples as $name => $S) {
+			$stats = $S->getStats();
+			switch ($type) {
+				case 'average':
+					printAverage($name, $stats);
+					break;
+				case 'dist_percentage':
+					printDistribution($name, $stats, true);
+					break;
+				case 'dist':
+					printDistribution($name, $stats);
+					break;
+				case 'questions':
+					echo "\"STATS ON QUESTIONS: ".strtoupper($name)."\"\n";
+					try {
+						$S->printStatsOnCommonItems();
+					} catch (Exception $e) {
+						echo "\"Not enough data\"\n";
+					}
+					break;
+				case 'marks':
+					$marks = $S->getMarks();
+					foreach ($marks as $student) {
+						echo implode(';', $student)."\n";
+					}
+					break;
+			}
+		}
+		echo "\n";
+	}
+}
+
+exit;
+
+function printDistribution($line_id = null, $stats = null, $percentage = false) {
+	if (is_null($line_id)) $line_id = "N/A";
+	if (is_null($stats)) {
+		echo "\"$line_id\",1,1.25,1.5,1.75,2,2.25,2.5,2.75,3,3.25,3.5,3.75,4,4.25,4.5,4.75,5,5.25,5.5,5.75,6\n";
+	} else {
+		echo "\"$line_id\"";
+		if (!$percentage) {
+			foreach ($stats['distribution'] as $n) echo ",$n";
+		} else {
+			foreach ($stats['distribution_percentage'] as $n) echo ",$n";
+		}
+		echo "\n";
+	}
+}
+
+
+function printAverage($line_id = null, $stats = null) {
+	if (is_null($line_id)) $line_id = "N/A";
+	if (is_null($stats)) {
+		echo "\"$line_id\",\"n\",\"tot\",\"average\",\"stddev\",\"median\"\n";
+	} else {
+		echo "\"$line_id\",\"{$stats['quarter_mark6']['n']}\",\"{$stats['quarter_mark6']['tot']}\",\"{$stats['quarter_mark6']['average']}\",\"{$stats['quarter_mark6']['stddev']}\",\"{$stats['quarter_mark6']['median']}\"\n";
+	}
+}
 
 exit;
 
 ?>
diff --git a/local/stats/lib/lib_amcstats.php b/local/stats/lib/lib_amcstats.php
index 48a4879..1cff011 100755
--- a/local/stats/lib/lib_amcstats.php
+++ b/local/stats/lib/lib_amcstats.php
@@ -1,418 +1,532 @@
 <?php
 
 # some functions for array_maps
 function clean_array($string) { return preg_replace('/"/', '', $string); }
 function decimal_conversion($string) { return preg_replace('/,/', '.', $string); }
 function square($n) { return($n*$n); }
 
 # standard deviation function (if PECL stats not available)
 if (!function_exists('stats_standard_deviation')) {
     function stats_standard_deviation(array $a, $sample = false) {
         $n = count($a);
         if ($n === 0) {
             trigger_error("The array has zero elements", E_USER_WARNING);
             return false;
         }
         if ($sample && $n === 1) {
             trigger_error("The array has only 1 element", E_USER_WARNING);
             return false;
         }
         $mean = array_sum($a)/$n;
         $carry = 0.0;
         foreach ($a as $val) {
             $d = ((double) $val) - $mean;
             $carry += $d * $d;
         }
         if ($sample) --$n;
         return sqrt($carry / $n);
     }
 }
 
 class AmcReader {
 	protected $filename = null;
 	protected $teacher = null;
 	protected $raw_data = null;
 	protected $columns = null;
 	protected $students = null;
+	protected $exam_points = null;
 
-	public function __construct($filename, $teacher, $max_points) {
+	public function __construct($filename, $teacher, $exam_points) {
 		if (!file_exists($filename))
 			throw new Exception('File not found: '.$filename);
 		$this->filename = $filename;
 
 		$this->teacher = $teacher;
+		$this->exam_points = $exam_points;
 
 		$raw_data = file($this->filename, FILE_IGNORE_NEW_LINES);
 		$this->raw_data = array();
 		foreach($raw_data as $line) {
 			$line = array_map("clean_array", explode(';', $line));
 			$line =  array_map("decimal_conversion", $line);
 			$this->raw_data[] = $line;
 		}
 		$this->parseHeader();
 		$this->parseStudents();
 	}
 
 	public function getStudents() {
 		return $this->students;
 	}
 
 	protected function parseHeader() {
 		foreach($this->raw_data[0] as $col_id => $value) {
 			// Analyse header from CSV file, based on content
 			$item = array();
 			switch ($value) {
 				case "ID":
 				case "NAME":
 				case "EMAIL":
 				case "SECTION":
 				case "Mark":
 					$item['name'] = $value;
 					$item['type'] = "info";
 					break;
 				case "SCIPER":
 					$item['name'] = $value;
 					$item['type'] = "unique_id";
 					break;
 				default:
 					$item['name'] = $value;
 					if (preg_match('/^TICKED:/', $value)) {
 						$item['name'] = preg_replace('/^TICKED:/', '', $value);
 						$item['type'] = "ticked";
 					} else {
 						$item['type'] = "question";
 						$item['subtype'] = $this->guessSubtype($col_id);
 					}
 					
 			}
 			// Stats will be computed at a later stage
 			$item['stats'] = null;
 			$this->columns[] = $item;
 		}
 	}
 
 	protected function guessSubtype($col_id) {
 		$subtype = null;
 		//$ticked_col = $this->getColIdsByType('ticked', $this->getQuestionNameByColId($col_id));
 		$min_points = 0;
 		$max_points = 0;
 		foreach($this->raw_data as $line) {
 			if (preg_match('/\./', $line[$col_id]))	return 'open';
 			if ($line[$col_id] > $max_points) $max_points = $line[$col_id];
 		}
 
 		if ($max_points == 3) return 'mc';
 		if ($max_points == 1) return 'tf';
 		return 'unknown';
 	}
 
 	protected function getColIdByName($name) {
 		foreach ($this->columns as $id => $col) if ($col['name'] == $name) return $id;
 		throw new Exception('Column not found: '.$name);
 	}
 
 	protected function getColIdsByType($type, $name = null) {
 		$ids = array();
 		if (is_null($name)) {
 			foreach ($this->columns as $id => $col) if ($col['type'] == $type) $ids[] = $id;
 		} else {
 			foreach ($this->columns as $id => $col) if ($col['type'] == $type and $col['name'] == $name) $ids[] = $id;
 		}
 		if (count($ids) == 0) {
 			if (is_null($name)) throw new Exception('Column type not found: '.$type);
 			throw new Exception('Column type not found: '.$type.'/'.$name);
 		}
 		if (count($ids) == 1) return $ids[0];
 		return $ids;
 	}
 
 	protected function getQuestionNameByColId($id) {
 		if (array_key_exists($id, $this->columns) and $this->columns[$id]['type'] == 'question')
 			return $this->columns[$id]['name'];
 		throw new Exception('Column not found, or is not a question: '.$id);
 	}
 
 	protected function parseStudents() {
 		foreach($this->raw_data as $line => $student) {
 			if ($line == 0) continue; // skip header
 
 			$data = array('teacher' => $this->teacher);
 			foreach(array('ID', 'SCIPER', 'NAME', 'EMAIL', 'SECTION') as $key) {
 				$data[$key] = $student[$this->getColIdByName($key)];
 			}
 
 			// Get points
 			$points = array();
 			$data['items'] = array();
 			foreach($this->getColIdsByType('question') as $col) {
 				$item = array();
 				$item['name'] = $this->getQuestionNameByColId($col);
 				$item['points'] = (float)$student[$col];
 				$item['right'] = (int)($item['points']>0);
 				$points[] = $item['points'];
 				$item['ticked'] = $student[$this->getColIdsByType('ticked', $item['name'])];
 				$item['type'] = $this->columns[$col]['type'];
 				$item['subtype'] = $this->columns[$col]['subtype'];
 				$data['items'][] = $item;
 			}
 
 			$data['total'] = array_sum($points);
 
 			$data['present'] = (int)(array_sum(array_map("square", $points))>0);
 
+			$data['exam_points'] = $this->exam_points;
+
+			// Compute marks
+			if ($data['present']) {
+				$data['positive_total'] = (float)max($data['total'], 0.0);
+				$data['mark6'] = (float)min($data['positive_total']/($this->exam_points)*5.0+1, 6.0);
+				$data['quarter_mark6'] = (float)round($data['mark6']*4.0, 0)/4.0;
+			} else {
+				$data['positive_total'] = 'n/a';
+				$data['mark6'] = 'abs';
+				$data['quarter_mark6'] = 'abs';
+			}
+
 			if (preg_match('/^FAKE/', $data['SCIPER'])) {
 				if ($data['present']) $data['type'] = 'unregistered';
 				else $data['type'] = 'unused';
 			} else $data['type'] = 'student';
 
 			$this->students[] = $data;
 		}
 	}
 }
 
 // Compare students on total (higher to lower)
 function cmp_total($a, $b)
 {
     if ($a['total'] == $b['total']) {
         return 0;
     }
     return ($a['total'] < $b['total']) ? 1 : -1;
 }
 
 class ExamCalcs {
 	protected $dataset = null;
 	protected $tmp_dataset = null;
 
 	public function __construct($dataset = null) {
 		$this->dataset = array();
 		if (!is_null($dataset)) $this->dataset = $dataset;
 	}
 
 	public function addFile($teacher, $teacher_file, $max_points) {
-		echo "Adding $teacher ($teacher_file) to the dataset ($max_points points).\n";
+		#echo "Adding $teacher ($teacher_file) to the dataset ($max_points points).\n";
 		$AR = new AmcReader($teacher_file, $teacher, $max_points);
 		$this->addDataSet($AR->getStudents());
 	}
 
 	public function addDataSet($data) {
 		foreach ($data as $student) $this->dataset[] = $student;
 	}
 
+	public function filterBySections($sections, $update = true) {
+		$dataset = array();
+		foreach ($this->dataset as $student) {
+			if (is_array($sections)) {
+				if (in_array($student['SECTION'], $sections))
+					$dataset[] = $student;
+			} else {
+				if ($student['SECTION'] == $sections)
+					$dataset[] = $student;
+			}
+		}
+		if ($update) $this->dataset = $dataset;
+		return $dataset;
+	}
+
 	public function filterByTeachers($teachers, $update = true) {
 		$dataset = array();
 		foreach ($this->dataset as $student) {
 			if (is_array($teachers)) {
 				if (in_array($student['teacher'], $teachers))
 					$dataset[] = $student;
 			} else {
 				if ($student['teacher'] == $teachers)
 					$dataset[] = $student;
 			}
 		}
 		if ($update) $this->dataset = $dataset;
 		return $dataset;
 	}
 
 	public function getTeachers() {
 		$teachers = array();
 		foreach ($this->dataset as $student) {
 			if (!in_array($student['teacher'], $teachers)) $teachers[] = $student['teacher'];
 		}
 		return $teachers;
 	}
 
 	public function getSections() {
 		$sections = array();
 		foreach ($this->dataset as $student) {
 			$section = $student['SECTION'];
 			if (!in_array($section, $sections) and $section != 'XXX') $sections[] = $section;
 		}
 		return $sections;
 	}
 
-	public function doStatsOnCommonItems() {
+	public function printStatsOnCommonItems() {
 		// Sort dataset by points
 		$dataset = $this->sortByTotalPoints(false);
 		if (count($dataset) < 3) throw new Exception('Dataset is too small.');
 
 		// Get items from the first student
 		$items = array();
 		foreach ($this->dataset[0]['items'] as $item) $items[] = $item['name'];
 
 		foreach ($dataset as $student) {
 			// Get items for current student
 			$tmp_items = array();
 			foreach ($student['items'] as $item) $tmp_items[] = $item['name'];
 			// Keep only items in both '$items' AND '$tmp_items'
 			$items = array_intersect($items, $tmp_items);
 		}
 
 		// Now, filter items in the dataset
 		$filtered_dataset = array();
 		foreach ($dataset as $student) {
 			if (!$student['present']) continue;
 			$filtered_items = array();
 			foreach ($student['items'] as $item) {
 				if (in_array($item['name'], $items)) $filtered_items[] = $item;
 			}
 			if (count($filtered_items)) {
 				$student['items'] = $filtered_items;
 				$filtered_dataset[] = $student;
 			}
 		}
 		$dataset = $filtered_dataset;
 		if (count($dataset) < 3) throw new Exception('Dataset is too small.');
 
-		// Computed limits
+		// Compute limits
 		$nb_students = count($dataset);
 		$twenty_seven = (int)($nb_students*27.0/100);
-		$upper_start = 0;
-		$lower_stop = $nb_students-1;
 		$upper_stop = $twenty_seven-1;
-		$lower_start = $lower_stop-$twenty_seven+1;
-
-		echo "$nb_students / $twenty_seven / $upper_start -> $upper_stop / $lower_start -> $lower_stop \n";
-	
-		$stats = array();
-		foreach ($items as $item_name) {
-			echo "$item_name\n";
-			$stats[$item_name] = array();
-			$stats[$item_name]['27%'] = $twenty_seven;
-			$stats[$item_name]['upper'] = 0;
-			$stats[$item_name]['lower'] = 0;
-
-			// Stats for upper 27%
-			for ($i = $upper_start ; $i <= $upper_stop; $i++) {
-				foreach($dataset[$i]['items'] as $cur_item) {
-					if ($cur_item['name'] == $item_name) {
-						if ($cur_item['right']) $stats[$item_name]['upper']++;
-					}
-				}
-			}
-			// Stats for lower 27%
-			for ($i = $lower_start ; $i <= $lower_stop; $i++) {
-				foreach($dataset[$i]['items'] as $cur_item) {
-					if ($cur_item['name'] == $item_name) {
-						if ($cur_item['right']) $stats[$item_name]['lower']++;
-					}
-				}
-			}
-			$stats[$item_name]['DI'] = (float)(($stats[$item_name]['upper']-$stats[$item_name]['lower'])/$twenty_seven);
-		}
+		$lower_start = $nb_students-$twenty_seven+1;
 
+		#echo "$nb_students / $twenty_seven / 0 -> $upper_stop / $lower_start -> $nb_students \n";
 
 		$stats = array();
 		foreach ($dataset as $i => $student) {
 			foreach ($student['items'] as $item) {
 				$name = $item['name'];
 				if (!array_key_exists($name, $stats))
-					$stats[$name] = array(	'27%'	=>	$twenty_seven,
-								'upper' =>	0,
-								'lower' =>	0,
-								'valid' =>	'?',
-								'ticked'=>	array(),
+					$stats[$name] = array(	'27%'	=>		$twenty_seven,
+								'upper' =>		0,
+								'lower' =>		0,
+								'valid' =>		null,
+								'ticked'=>		null,
 								'ticked_count'=>	0,
 								'empty_count'=>		0,
-								'type' =>	null,
-								'subtype' =>	null,
+								'type' =>		null,
+								'subtype' =>		null,
 								);
 				$stats[$name]['type'] = $item['type'];
 				$stats[$name]['subtype'] = $item['subtype'];
+
+				// Initialise 'ticked' table
+				if (is_null($stats[$name]['ticked'])) {
+					switch ($stats[$name]['subtype']) {
+						case 'mc':
+							$stats[$name]['ticked'] = array( 'A' => 0, 'B' => 0, 'C' => 0, 'D' => 0, 'multiple' => 0);
+							break;
+						case 'tf':
+							$stats[$name]['ticked'] = array( 'TRUE' => 0, 'FALSE' => 0, 'multiple' => 0);
+							break;
+						default:
+							$stats[$name]['ticked'] = array();
+							break;							
+					}
+				}
+
+				// Count right answers
 				if ($item['right']) {
-					if ($stats[$name]['valid'] == '?')
-						if ($item['subtype'] = 'tf') {
-							if ($item['ticked'] == 'A') $stats[$name]['valid'] = 'TRUE'; else $stats[$name]['valid'] = 'FALSE';
-						} else {
-							$stats[$name]['valid'] = $item['ticked'];
+					// Save valid answer
+					if (is_null($stats[$name]['valid'])) {
+						switch ($stats[$name]['subtype']) {
+							case 'tf':
+								if ($item['ticked'] == 'A')
+									$stats[$name]['valid'] = 'TRUE';
+								else
+									$stats[$name]['valid'] = 'FALSE';
+								break;
+							case 'mc':
+								$stats[$name]['valid'] = $item['ticked'];
+								break;
+							default:
+								$stats[$name]['valid'] = 'n/a';
+								break;
 						}
-					if ($i <= $upper_stop) {
-						$stats[$name]['upper']++;
-					}
-					if ($i >= $lower_start) {
-						$stats[$name]['lower']++;
 					}
+
+					// 'upper 27%' and 'lower 27%' counters
+					if ($i <= $upper_stop) 	$stats[$name]['upper']++;
+					if ($i >= $lower_start) $stats[$name]['lower']++;
 				}
+
+				// Count empty answers
 				if (empty($item['ticked'])) {
 					$stats[$name]['empty_count']++;
 				} else {
+					// Stats on non-empty answers
 					$stats[$name]['ticked_count']++;
 					if (strlen($item['ticked']) > 1) {
 						$stats[$name]['ticked'] = $this->createAndIncrement($stats[$name]['ticked'], 'multiple');
 					} else {
-						if ($item['subtype'] = 'tf') {
-							if ($item['ticked'] == 'A') $field = 'TRUE';
-							if ($item['ticked'] == 'B') $field = 'FALSE';
-							$stats[$name]['ticked'] = $this->createAndIncrement($stats[$name]['ticked'], $field);
-						} else {
-							$stats[$name]['ticked'] = $this->createAndIncrement($stats[$name]['ticked'], $item['ticked']);
+						switch ($item['subtype']) {
+							case 'tf':
+								if ($item['ticked'] == 'A') $field = 'TRUE';
+								if ($item['ticked'] == 'B') $field = 'FALSE';
+								$stats[$name]['ticked'] = $this->createAndIncrement($stats[$name]['ticked'], $field);
+								break;
+							case 'mc':
+								$stats[$name]['ticked'] = $this->createAndIncrement($stats[$name]['ticked'], $item['ticked']);
+								break;
+							default:
+								$stats[$name]['ticked'] = $this->createAndIncrement($stats[$name]['ticked'], $item['ticked']);
+								break;
 						}
 					}
 				}
 			}
 		}
 
-		// Compute more stats...
+		// Compute more stats
 		$tmp = array();
 		foreach ($stats as $name => $stat) {
 			// Discrimination index
 			$stat['DI'] = ($stat['upper']-$stat['lower'])/(1.0*$stat['27%']);
+
+			// Calculate percentages
+			$ticked_percentage = array();
+			foreach ($stat['ticked'] as $t => $n) {
+				$ticked_percentage[$t] = array( 'n' => $n, '%' => (float)(100.0*$n/$stat['ticked_count']), 'valid' => (int)($t == $stat['valid']));
+			}
+			$stat['ticked'] = $ticked_percentage;
 			$tmp[$name] = $stat;
 		}
 		$stats = $tmp;
 
-		print_r($stats);
+		// Print CSV
+		$previous_subtype = null;
+		$header = '"question_id","subtype","27 %","upper","lower","DI","count","valid"';
+		foreach ($stats as $name => $stat) {
+			if ($stat['subtype'] != $previous_subtype) {
+				#if (!is_null($previous_subtype)) echo "\n";
+				echo $header;
+				foreach ($stat['ticked'] as $answer => $data) echo ",\"[$answer] count\"";
+				foreach ($stat['ticked'] as $answer => $data) echo ",\"[$answer] %\"";
+				echo "\n";
+				$previous_subtype = $stat['subtype'];
+			}
+			echo "$name,{$stat['subtype']},{$stat['27%']},{$stat['upper']},{$stat['lower']},{$stat['DI']},{$stat['ticked_count']}";
+			foreach ($stat['ticked'] as $answer => $data) if ($data['valid'] == 1) echo ",\"$answer\"";
+			foreach ($stat['ticked'] as $answer => $data) echo ",{$data['n']}";
+			foreach ($stat['ticked'] as $answer => $data) echo ",{$data['%']}";
+			echo "\n";
+		}
+
 	}
 
 	public function sortByTotalPoints($update = true) {
 		if ($update) {
 			usort($this->dataset, "cmp_total");
 			return $this->dataset;
 		} else {
 			$dataset = $this->dataset;
 			usort($dataset, "cmp_total");
 			return $dataset;
 		}
 	}
 
 	public function getDataSet() {
 		return $this->dataset;
 	}
 
 	protected function createAndIncrement($table, $field, $increment = 1) {
 		if (!array_key_exists($field, $table)) {
 			$table[$field] = 0;
 		}
 		$table[$field] += $increment;
 		return $table;
 	}
 
-	public function doStats() {
+	public function getMarks() {
+		$marks = array();
+		foreach($this->dataset as $student) {
+			$tmp = array();
+
+			$tmp['teacher'] = $student['teacher'];
+			$tmp['ID'] = $student['ID'];
+			$tmp['SECTION'] = $student['SECTION'];
+			$tmp['exam_points'] = $student['exam_points'];
+			$tmp['total'] = $student['total'];
+			$tmp['present'] = $student['present'];
+			$tmp['SCIPER'] = $student['SCIPER'];
+			$tmp['quarter_mark6'] = $student['quarter_mark6'];
+			$marks[] = $tmp;
+		}
+		return $marks;
+	}
+
+	public function getStats() {
 		$stats = array();
 
 		# Presence
 		$stats['presence'] = array();
+		$marks = array();
+		$stats['quarter_mark6'] = array( 'n' => 0, 'tot' => 0, 'average' => null, 'stddev' => null, 'median' => null);
 		foreach($this->dataset as $student) {
-			// Create category if need be
+
+			// Presence
 			$stats['presence'] = $this->createAndIncrement($stats['presence'], 'total');
 			switch ($student['type']) {
 				case 'student':
 					if ($student['present']) {
 						$stats['presence'] = $this->createAndIncrement($stats['presence'], 'present');
 					} else {
 						$stats['presence'] = $this->createAndIncrement($stats['presence'], 'absent');
 					}
 					break;
 				case 'unused':
 					$stats['presence'] = $this->createAndIncrement($stats['presence'], 'unsused');
 					break;
 				default:
 					$stats['presence'] = $this->createAndIncrement($stats['presence'], 'unknown');
 					
 			}
+
+			// Average
+			if ($student['present']) $marks[] = $student['quarter_mark6'];
 		}
-		print_r($stats);
+		$stats['quarter_mark6']['n'] = count($marks);
+		if ($stats['quarter_mark6']['n'] > 0) {
+			$stats['quarter_mark6']['tot'] = array_sum($marks);
+			$stats['quarter_mark6']['average'] = $stats['quarter_mark6']['tot']/$stats['quarter_mark6']['n'];
+			$stats['quarter_mark6']['stddev'] = stats_standard_deviation($marks);
+			sort($marks);
+			$stats['quarter_mark6']['median'] = $marks[round(count($marks)/2)];
+		} else {
+			$stats['quarter_mark6']['tot'] = 0;
+			$stats['quarter_mark6']['average'] = 0;
+			$stats['quarter_mark6']['stddev'] = 0;
+			$stats['quarter_mark6']['median'] = 0;
+		}
+		
+		// Distribution (of marks)
+		$distribution = array();
+		for ($m = 1.0 ; $m <= 6.0 ; $m += 0.25) $distribution[(string)$m] = 0;
+		$stats['distribution_total'] = 0;
+		foreach ($marks as $mark) {
+			$distribution[(string)$mark]++;
+			$stats['distribution_total']++;
+		}
+		$stats['distribution'] = $distribution;
+		$stats['distribution_percentage'] = array();
+		if ($stats['quarter_mark6']['n']) {
+			foreach ($stats['distribution'] as $mark => $count) $stats['distribution_percentage'][$mark] = $count*100.0/$stats['distribution_total'];
+		} else {
+			$stats['distribution_percentage'] = $stats['distribution'];
+		}
+
+		return($stats);
 	}
 
 }
 
 ?>