Anyone with some Cisco certification experience knows that the exams are adaptive in nature. If you miss a question on subjet X, the test engine weighs questions on that subject heavier in its test pool and you will receive more questions on that subject.
After recently sitting several certification exams, I would suggest that this is also true for not only questions you miss, but questions you spend more time on than others. I sat an exam yesterday and noticed that after pondering for a very long time on a simple single answer multiple choice question, I started receiving more and more questions on that subject.... which in the grand scheme of test subjects is a relatively very very small and nearly insignificant subject (whether port security is allowed on voice vlans).
Anyway, I thought I'd pass this insight on.