Applying To Colleges

[Antarctic]

As an elderly foreigner I have only a vague idea of what GPA and SAT mean let alone any concept of "weighting".
I know I could google them but I'd sooner have some first hand explanations.

A few questions...assuming SAT is an examination when do you sit it and can you make further attempts in order to improve your results?
Is your GPA an ongoing score through your high school career?
What are average scores and really good scores?
What is "weighting"?

Our universities are competing for students so they'll accept anyone (as long as they can pay or get a student loan).It can difficult to get into individual programmes e.g. medicine but they'll accept any undergraduates.
Of course all our universities are government-funded and not privately run.

[Antarctic]

A few questions...assuming SAT is an examination when do you sit it and can you make further attempts in order to improve your results?
Is your GPA an ongoing score through your high school career?
What are average scores and really good scores?
What is "weighting"?

The SAT is a privately run examination that tests one's "reasoning" ability. While the company (College Board) offers watered-down versions of it to younger grades, the actual test is taken between the middle of 11th grade to early 12th. You can take it multiple times, and since it's made up of three sections you can combine the best score in each section for a "superscore".
American GPA is an average of your grades from 9th grade, the first year of high school. Almost all involves assigning points to a grade or a range of percentages, hence "Grade Point Average". GPA is all relative, though to apply for top private schools a GPA of at least 3.8 out of 4.0 is necessary.
So far I have only described the unweighted GPA, but because many high schools have advanced "honours" or university-level Advanced Placement courses, taking those means you're graded on a higher scale. For an AP course, the highest point possible could be a 5.0 while a C grade is still worth 3.0. The bonuses you gain for taking these courses account into the weighted GPA, which can exceed the 4.0 barrier of the unweighted one.

Our universities are competing for students so they'll accept anyone (as long as they can pay or get a student loan).It can difficult to get into individual programmes e.g. medicine but they'll accept any undergraduates.
Of course all our universities are government-funded and not privately run.

Don't think that most private schools aren't competing for students either! The problem is that Americans can apply to many, many schools with the advent of technology, and as you can see all of these kids try for the top 20 in the country. These schools have low admission rates, but outside this bubble there are many people who are willing to go to a public state school.

Thanks...I appreciate your reply.

I guess population size is the big difference...we have thousands of new entrants each year and the Americans must just about have millions.

It's only been in recent decades that University educations have moved away from just being for the academic elite....in the early 1970's I was one of a student body of 4,000.The same University now has over 20,000 students.
The big difference was that it used to be entirely government funded...not only did I have no loan but the Government paid me to study.Nowadays it's a revenue gatherer for the universities as they charge tuition fees directly to the students and receive government funding based on their student rolls....more students,more money.