public function getAverageYears() { /*get average number of years a student stays in the university 1. get number of students with studentterms, remove dropouts 2. get number of years of each student by dividing number of terms by 3 3. get average of step 2 (accdng to a site, sum/count is faster than avg command) */ $numberOfYearsPerStudent = Studentterm::getNumberofYears(); $numberOfStudents = count($numberOfYearsPerStudent); $totalYears = 0; foreach ($numberOfYearsPerStudent as $key => $val) { $totalYears = $totalYears + $val->numyears; } $aveYearsOfStay = round($totalYears / $numberOfStudents, 2); return $aveYearsOfStay; }