You give a standardized statistics exam for which the scores are normally distributed with a mean score of 750 and a standard deviation of 100.
a. What is the probability of a score greater than 800?
b. What is the probability of a score lower than 550?
c. What is the probability of a score between 650 and 900?
d. The top 10% of all exam takers will score at least ______on the exam?