Viv- the median UAI is 98 in our school, so essentially if you are gaining average in all your subjects then you would be around the middle of the school hypothetically. Of course this isn't exactly true since different subjects will scale differently, you could have a dumb class or whatever.. but it's based on past years performance. Don't forget that our school averages are artificially modified to allow for differentiation of students and comparisons. The average is always brought down (or up) to between 75% and 85%, and the standard deviation has a special formula which our school uses. Prior to submission to the Board of Studies, our raw marks are supposedly "boosted" to make them more in line with what would be expected across the state, however, the big boost comes when the marks are aligned (after the HSC exams) with other schools.
To ragerunner- course is referring to the subject- eg. English Advanced is a course, IPT is a course, Economics is a course. Average refers to our school's average mark in these courses.