Question 4 - Normal Distribution (10 marks)

The time needed to complete final examination in a particular college course is normally distributed with a mean of 160 minutes and a standard deviation of 25 minutes. Answer the following questions:

a) What is the probability of completing the exam in 120 minutes or less? (2 marks)

b) What is the probability that a student will complete the exam in more than 120

minutes but less than 150 minutes? (2 marks)

c) What is the probability that a student will complete the exam in more than 100

minutes but less than 170 minutes? (2 marks)

d) Assume that the class has 120 students and that the examination period is 180 minutes

in length. How many students do you expect will not complete the examination in the allotted time? (4 marks).