My band director in high school, Robert Spevacek, used to say that it takes 10 times playing a musical passage correctly to erase one time playing it incorrectly. Here is a study that comes to some of the same conclusions.
I was reading through my niece’s Facebook page and found this interesting article about a study done by Noa Kageyama on musical practice. My niece, Sarah Minette, is a middle school band director, saxophone player, and is doing doctoral work at ASU. Check it out. http://www.creativitypost.com/psychology/8_things_top_practicers_do_differently