No, I go to a mid 30s school. My friend goes to a top 5 school. I am performing much better at my school than he is at his school (relative of course). I am almost in top 10 in all my subjects, and he's last in about 3 subjects and near last in the rest. I was just wondering how well he is doing relative to me.
It's impossible to definitively say. We don't know the strength of both the schools - yes, he goes to a top 5 school, based on a ranking system that looks at the percentage of Band 6's. But that doesn't show how poor or how well the tail might perform. Even 10th in a top 30 school may not achieve an exam mark on par with someone coming last in another school. It's simply impossible to say. That's why if you look at the historical trends and see what ATARs are typical of your ranks.
If I were to guess, I'd say you'll achieve the better ATAR because even the tail (say bottom 10-20%) of James Ruse does
worse than the top 10% of a 30-40th ranked school (based on when I sat the HSC). Of course the subjects and individual marks dictate this, but we can surmise this based on anecdotes.