public function getStatistics(Exercise $exercise, $maxScore)
    {
        return [
            'maxScore' => $maxScore,
            'nbSteps' => $exercise->getSteps()->count(),
            'nbQuestions' => $this->exerciseRepository->countExerciseQuestion($exercise),
            'nbPapers' => $this->paperManager->countExercisePapers($exercise),
            'nbRegisteredUsers' => $this->paperManager->countPapersUsers($exercise),
            'nbAnonymousUsers' => $this->paperManager->countAnonymousPapers($exercise),
            'minMaxAndAvgScores' => $this->getMinMaxAverageScores($exercise, $maxScore),
            'paperSuccessDistribution' => $this->getPapersSuccessDistribution($exercise, $maxScore),
            'paperScoreDistribution' => $this->getPaperScoreDistribution($exercise, $maxScore),
            'questionsDifficultyIndex' => $this->getQuestionsDifficultyIndex($exercise),
            'discriminationCoefficient' => $this->getDiscriminationCoefficient($exercise),
        ];
    }