Standardized Tests

What exactly do standardized tests prove? That you can fill in a bubble on a Scantron sheet? Do they really give accurate results?
Multiple-choice standardized tests do not give accurate results. When asked a question with four possible answers you immediately have a twenty- five percent chance of choosing the correct answer. Usually there will be two answers that are obviously wrong to even the dumbest students. After eliminating the two obviously wrong answers, the student has a fifty percent chance of choosing the correct answer. That shows absolutely nothing except that most people have enough sense to eliminate the most obviously wrong answers and, by chance, choose a correct answer. It doesn't take a genius to know that Howard Stern and Mesopotamia have nothing to do with each other. Yes, Howard Stern was one of the choices on my sixth grade social studies test.
One test score can decide whether or not a student passes a class. Even if you normally do well in a class, if you fail the test, you fail that class and may not be able to graduate from high school. Exams like the Math A exam can decide if you get your diploma.
But why would a normally good student do badly on a standardized test? It's far too stressful for the students to do well. Parents, teachers, and school officials are all putting extreme pressure on students to do well on these tests. Students are under so much stress, they cry through the whole tests. They can't sleep in the nights before the tests because they're up worrying and studying. Besides that, not everyone is good at standardized tests. Some of us are better at, prefer, tests that ask for essays and written answers. The least the test makers could do is realize that filling in 200+ bubbles isn't really helping anyone.
On the day of the tests you have to get #2 pencils, a chunk eraser, a book, scrap paper and a calculator. For one thing, sharpened pencils with erasers, scrap paper and calculators for those who need them should definitely be provided. The school should also give the students something to boost energy before the test. Each student taking the test should at least get a cup of orange juice a few minutes before the test.
These tests shouldn't be so stressful. For one thing, whether or not you graduate from high school shouldn't rest on the test score. Secondly, the teachers shouldn't start making you cram everything you've learned from 8th to 11th grade in a month so you have a chance of passing.
Valuable time is wasted learning the test. In that month of cramming, aren't there other things that you could be learning? Don't you have better things to do with your time than hoping that you might be able get your diploma or not put in AIS classes?
I understand that standardized testing is useful for getting statistics. But should the scores on these tests decide how your education and life goes? Should standardized tests be this powerful?
Some argue that standardized tests can detect learning disabilities. In some cases they can, but there are other ways. To figure out if someone has a learning disability, someone needs to suspect that it's there or no one's going to be looking for it. Maybe the student just doesn't care. That doesn't make him or her learning disabled, does it?
There is no reason for standardized tests. Students are under enough stress as it is, and they don't need any more. We are under so much pressure to do well; it's not in any way justifiable.