Mean 2.6cm
the probability that a mans nose sticks out more than 2.8cm is 0.04. if you look at 500 men how many would you expect to have a nose that sticks out more that 2.8 cm

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. 

Ithink it's dissoulution

Its probably the possible factors tt, tt, tt,