Recently, a teacher investigated the effectiveness of self-study at home by giving her 15 students (A〜O) two English tests three months apart. ... It is not easy to draw conclusions about the relationship between the amount of self-study and score change, but it seems fair to say that studying longer than 20 hours per week serves reliably to improve scores, as (41) of the two students in this category scored higher on the second test.
――慶応義塾大学 商学部(2月18日実施)――2004年