The Chapin Social Insight Test evaluates how accurately the subject appraises other people. In the reference population used to develop the test, scores are approximately normally distributed with mean 20 and standard deviation 4. The range of possible scores is 0 to 48. (a) What proportion of the population has scores below 16 on the Chapin test?

(b) What proportion has scores below 8?

(c) What proportion has scores above 28?

(d) How high a score must you have in order to be in the top quarter of the population in social insight?