8. A machine operation produces bearings whose diameters are normally distributed,
with a mean of 0.498 inch and a standard deviation of 0.002 inch. Suppose that
specifications require that the bearing diameter be 0.500 inch plus or minus 0.004
inch.
a) What proportion of the production will be unacceptable?
b) A quality control inspector selects bearings from the production independently and at
random. What is the probability that the first unacceptable bearing will be the sixth one
selected?
c) What is the probability that the third unacceptable bearing will be the sixth one selected?

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