Most people could probably benefit from some anger management classes. That said, it really depends on the type of test you were given. Was it administered by a mental health professional, in a clinical setting? If it was, its probably pretty spot on, and you should go ahead and take the classes. If it was an online test given at your probation officers desk, its probably not at all valid, and you should insist on a proper test, given by a professional. You could also speak to your doctor and get some input from someone who has treated you medically and presumably knows you fairly well.