FERPA regulations require that the school district allow you access to information about the tests taken and their complete results (not just the summary they have told you). I am not sure who they would have given the tests to for scoring, but there should be some example test and a copy of his results that you have a right to see. (Most standardized tests like that send back an answer key showing which questions each child got right and wrong and what this means in terms of the tests' norms. If you want to know more about the test tell them you have a legal right to see whatever information they have about the test and his scores.