[Reach]

It's well established in the literature that sleep depriving yourself leads to decreased response speed and increased variability in performance especially on tasks involving alertness, attention and vigilance...

i.e. not sleeping will have a statistically significant effect on factors you need in order to do well on tests.


Study as hard as you can, but get some sleep before the exam. Otherwise, your studying won't help you much because you'll lack the basic cognitive functions usually required for exams. Consider cramming, sleeping and then cramming again before the exam in the morning.