Dear Inayat, the outcome of any event cannot be determined before the event occurs. No one would know who is a better student or a weaker student until the exam results are released. Not at least the exam conducting authorities or the computer system which disintegrates students into shifts based on their own criteria. And you can't define a "better" and a "weaker" student just for an exam shift. And an exam conducting authoritative body is beyond any prejudice over the academic excellence of a candidate.