SELECT university, q2.difficult_level, ROUND(COUNT(q1.question_id)/COUNT(DISTINCT q1.device_id), 4) AS avg_answer_cnt FROM user_profile u INNER JOIN question_practice_detail q1 ON u.device_id = q1.device_id INNER JOIN question_detail q2 ON q1.question_id = q2.question_id GROUP BY univ...