Before revision: Technically, the term includes errors due to mechanical failure or slips of the hand or finger, but excludes errors of ignorance, such as spelling errors, or changing and misuse of words such as "than" and "then".
After revision: Technically, the term includes errors due to mechanical failure or slips of the hand or finger, but excludes errors of ignorance, such as spelling errors, or changing and misue of wods such as "than" and "then".