The two main college admissions tests are SAT (Scholastic Aptitude Test) and ACT (American College Testing). Each of these tests generates a high degree of angst for juniors and seniors. I suppose a certain amount of concern is justified especially if you have not been a good student during your middle and high schools.
What is the purpose of these tests?
Both SAT and ACT are deigned to assess a student's readiness for college level academic work.
"The SAT and SAT Subject Tests
are designed to assess your academic readiness for college. These exams provide a path to opportunities, financial support, and scholarships, in a way that's fair to all students. The SAT and SAT Subject Tests keep pace with what colleges are looking for today, measuring the skills required for success in the 21st century."
This clip from the College Board explains what the SAT is.
Here is a brief description of what the ACT test
"The ACT is a national college admissions examination that consists of subject area tests in: English, Mathematics, Reading &Science
The ACT Plus Writing includes the four subject area tests plus a 30-minute Writing Test.
ACT results are accepted by all four-year colleges and universities in the US.
The ACT includes 215 multiple-choice questions and takes approximately 3 hours and 30 minutes to complete, including a short break (or just over four hours if you are taking the ACT Plus Writing). Actual testing time is 2 hours and 55
. . .read more