how you go depends on what the people above and below you get. your assessment mark is around the mark the someone at your school gets in the actual exam. this is why rank is important and everone elses performance. if you stuff your exam you rely on good result from othere people. basically the average of your year at school will become the average mark in the exam., so if you go to a good school the average will be better or will be moderated better cause they do better in the exams
hope i wasnt confusing