It varies depending on what you want to study. Typically engineering combined with something e.g. commerce or science can be up to 5 or 6 years full time depending on the university. Commerce is usually 3 years full time.
Re: how can I know a course is right for me and I will enjoy it?
You can always transfer after a year if you have the marks. You'll never really know if you're going to enjoy what you're choosing to study.
Semester 2, 2012
ECON1102:
Ease: 6/10 I expected this to be my WAM booster, although it's entirely my fault. I left study til the day before (for midsession and final exam) and got a very poor mark.
Lecturer: x/10 Never went to Commerce lectures.
Interest: 9/10 Although I touched my textbook...
Studying maths at uni will help develop a lot of skills and attributes that your future employers desire. As Trebla said, it may help to some extent but it's not going to be a dealbreaker when you look for jobs as a trader.
I agree with these two. Uni maths is very different to high school maths; just because you're good at and enjoy high school maths doesn't mean you'll be good at and enjoy uni maths, and vice versa. I've been tutoring Extension 2 for almost 2 years now but at times I still find it fairly...
Statistical Inference isn't offered in S2 if you're talking about the one offered by the School of Maths and Stats.
And I highly doubt stats that 'we' do is the same as psych stats. I see no use for discrete-time or continuous-time Markov chains in Psychology.