The score on an exam from a certain statistics class, , is normally distributed with and .

NOTE: Assume for the sake of this problem that the score is a continuous variable. A score can thus take on any value on the continuum. (In real life, scores are often treated as if they were continuous values but are actually discrete in most cases.)

(a) Write the event ''a score equal to 66.8'' in terms of : .

(b) Find the probability of this event:

(c) Find the probability that a randomly chosen score is greater than 85.8: .

(d) Find the probability that a randomly chosen score is between 66.8 and 85.8: .

You can earn partial credit on this problem.