Klinefelter syndrome, alternatively known as XXY, is a genetic disorder characterised by the presence of an extra X chromosome. The disorder only affects males. Suppose a researcher estimates that the probability that a newborn male will have Klinefelter syndrome is 0.0018. Suppose that a particular hospital delivers 1205 male babies in a year.

It depends on the subject for me. some exams are easier than others so i usually go through it and answer questions i know based on my general knowledge, then double check after. going through the lesson can a lot  because the exams can be  very lesson-specific, but sometimes they are ridiculously long so a lot of people don't take the time. i did find that, when i went through the lessons, i was making 100's on my exams vs strictly using + the internet and  i make 90's.