xkingko

Your school guesses.
Usually the academic advisor or principle.
Best ways to improve this:
1. High ranks in all your subjects
2. Ask them really nicely to circle above 95.5

You need to get your school to fill in and submit this form to the uni: http://www.uws.edu.au/__data/assets/pdf_file/0019/462502/2013_Pred_ATAR_form.pdf

Basically, your school estimates what ATAR you will get and then fills in the form.
Then if your predicted ATAR is high enough UWS will look at your UMAT, if you score within roughly the top 160 GWS applicants for UMAT (1:1:0.5) you get an interview offer.
BUT, if they give you a lower predicted ATAR then you won't get an offer.
BUT, if after ATARs are released you get above the cutoff your UMAT is then looked at to see if it was above the GWS applicant offered an interview, if it is you will be interviewed with the interstate students in January.

A lot of first semester is related to biology.

And like, biology introduces basic anatomy in high school, which is obviously slightly relevant to med school.