Ball bearings are manufactured with a mean diameter of 6 millimeters (mm). Because of the inherent manufacturing process variability, the lots of bearings are approximately normally distributed with a standard deviation of 0.03 mm.

What proportion of ball bearings has a diameter of greater than 6 mm?

1. 0.4562
2. 0.50
3. 0.6554
4. 0.7500

What proportion of ball bearings has a diameter of more than 6.03 mm?

1. 0.1339
2. 0.1587
3. 0.84134
4. 8.066

Any bearing having a diameter of less than 5.95 mm or greater than 6.05 mm are discarded. What proportion of the bearings will be discarded?

1. 0.0956
2. 0.9522
3. 1
4. 3.159

Using the result of the previous question, if 40,000 ball bearings were to be manufactured, how many would the manager have to discard?

1. 3,824
2. 38,088
3. 40,000
4. 126,360