A magnetic disk drive manufacturer produces precision bearings with the diameter which follows normal distribution having mean value of 0.2508 inches and standard deviation of 0.0008 inches. The specified tolerance for the bearing is 0.2500 ± 0.0015 inches. Bearings outside of the tolerance range must be recycled at cost to the manufacturer of $4.20 per rejected bearing. If the manufacturer produces a 1000 bearings per week, determine:
a) the number and cost of rejected bearings each week,
b) the annual (one year) savings the company could achieve if the manufacturing process could be modified to producing bearings with the same standard deviation, but mean size of 0.2500 inches