posted by josh .
The inside diameter of metal washers produced by a company are normally distributed with a mean of .5 inches and a standdrd deviation of .01 inches. Of all washers produced .8% of the washers are rejected because they are too small for a bolt used to test them. What is the diameter of the bolt used for the test?
Rejection rate = 0.8% = 0.008
rejection criterion = z<Z
From normal distribution tables
Ans: washers with diameters less than 0.476 are rejected.