Ball bearings are manufactured with a mean diameter of 5 millimeters (mm). Because of variability in the manufacturing process, the diameters of the ball bearings are approximately normally distributed with a standard deviation of 0.02mm.

(a) what proportion of ball bearings has a diameter more than 5.03mm?

(b) Any ball bearings that have a diameter less than 4.95mm or greater than 5.05mm are discarded. What proportion of ball bearings will be discarded.

(c) Using the result of Part B, if 30,000 ball bearings are manufactured in a day, how many should the plant manager expect to discard?