I do understand that there should be some kind of standard or way to measure how students comprehend what they are learning. Colleges often use them to determine how successful a student may be in certain college courses. If you get low math scores on your standardized exams, you will probably have to take some prep classes before you can enroll in certain college courses.
These scores are to give them an indication of what your skill level and aptitude for certain areas are. Generally speaking if you have high math and science scores, you will do well in college math and engineering courses. If you have high scores in reading, you should not have trouble with English and education courses.