A distribution of scores on a Psychopathology module test has a mean of =80 and a standard deviation of =10. For the population of students who have taken the test; (8 marks)

a. What proportion have scores greater than 90?

b. What proportion have scores less than 75?

c. What proportion have scores between 85 and 90?

d. If an advanced module only accepts students who scored in the top 30%, what is the minimum score needed to be accepted?