public function getMinMaxAverageScores(Exercise $exercise, $scoreOn)
    {
        $papers = $this->paperRepository->findBy([
            'exercise' => $exercise,
        ]);

        $scores = $this->getPapersScores($papers, $scoreOn);

        $result = [
            'min' => 0 === count($scores) ? 0 : min($scores),
            'max' => 0 === count($scores) ? 0 : max($scores),
        ];
        $average = 0 === count($scores) ? 0 : array_sum($scores) / count($scores);
        $result['avg'] = $average !== floor($average) ? floatval(number_format($average, 2)) : $average;

        return $result;
    }