Middle Vale High School is a small school where the students are competitive and parents are very concerned with test scores and report card grades. Shannon Marsh complained to her parents that her grade of a B on a paper was unfair because she put as much effort in as her friend who received an A. The parents chose to confront the teacher and demand an explanation as to the variance in grades. Which would be the most effective tool for the teacher to be able to demonstrate how she derived the grade?