Two of the items reflect two types of bias. Grades result from a person's intelligence and self-discipline. When these are high, grades are good and vice versa. Grades depend on doing the right things. A person earns good grades for following the rules and bad grades for slipping up.
Grades depend on quality teaching and educational materials.
A person does well when quality is high and vice versa. I got a bad grade because the teacher wrote tricky questions that had nothing to do with what we talked about in class.