The GRE is widely used to help predict the performance of applicants to graduate schools. The range of possible scores on a GRE is 200 to 900. The psychology department at a university finds that the students in their department have scores with a mean of 544 and standard deviation of 103.

a. Find the probability that a student in the psychology department has a score less than 480.

b. Find the probability that a student in the psychology department has a score between 480 and 730.