Some people get pointers immediately after one exposure before puberty. Not every student needs to practice. Some people, who maybe never came to your univers

Some people get pointers immediately after one exposure before puberty. Not every student needs to practice. Some people, who maybe never came to your university at all, will never get linear algebra matter how much they practice. To say the distribution is unimodal is one claim. It's another matter to claim the distribution is narrow.