The purpose of the sample test is to allow you to experience the environment of the real test which is coming up. Most of the questions on both the sample test and the real test are recycled homework questions. The fact that a question appears on the sample test means nothing. (The question is no more or less likely to appear on the real test than any other homework question.) With the sample test, all students get the same sample test (except for randomized numbers in the questions). With the real test, each student gets a unique version of the test. This means that if you were to see another student’s version of the real test, it would provide no more information about your own test than this sample test does. On the sample test, everybody’s questions appear in the same order (so that you can easily compare with classmates if you want to talk about the sample test). On the real test, the choice of questions is randomized for each student, the numbers within the questions are randomized, and the order of the questions is randomized. So there is no correlation whatsoever between your test and anyone else’s.
As indicated above, the main purpose of the sample test is to give you experience working in a timed environment with a 3-submission limit. Other than that, there’s not much difference in doing the sample test and reviewing your homework. Your real test will likely have a few questions (2 to 4) that are not recycled homework questions, but they will be similar enough in terms of what they require that you may not even notice which questions they are.