Human visual inspection of solder joints on printed circuit boards can be very subjective. Part of the problem stems fro
Posted: Sun Sep 05, 2021 5:10 pm
Human visual inspection of solder joints on printed circuit
boards can be very subjective. Part of the problem stems from the
numerous types of solder defects (e.g., pad nonwetting, knee
visibility, voids) and even the degree to which a joint possesses
one or more of these defects. Consequently, even highly trained
inspectors can disagree on the disposition of a particular joint.
In one batch of 10,000 joints, inspector A found 724that were
judged defective, inspector B found 751 such joints, and 1159 of
the joints were judged defective by at least one of the inspectors.
Suppose that one of the 10,000 joints is randomly selected.
(a) What is the probability that the selected joint was judged
to be defective by neither of the two inspectors?
(b) What is the probability that the selected joint was judged
to be defective by inspector B but not inspector A?
boards can be very subjective. Part of the problem stems from the
numerous types of solder defects (e.g., pad nonwetting, knee
visibility, voids) and even the degree to which a joint possesses
one or more of these defects. Consequently, even highly trained
inspectors can disagree on the disposition of a particular joint.
In one batch of 10,000 joints, inspector A found 724that were
judged defective, inspector B found 751 such joints, and 1159 of
the joints were judged defective by at least one of the inspectors.
Suppose that one of the 10,000 joints is randomly selected.
(a) What is the probability that the selected joint was judged
to be defective by neither of the two inspectors?
(b) What is the probability that the selected joint was judged
to be defective by inspector B but not inspector A?