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发帖数: 129 | 1 85% of the cabs in the city are Green and 15% are Blue.
A witness identified the cab as Blue. The court tested the reliability of
the witness under the circumstances that existed on the night of the
accident and concluded that the witness correctly identified each one
of the two colors 80% of the time and failed 20% of the time.
What is the probability that the cab involved in the accident was
Blue rather than Green? | j**y
发帖数: 1 | 2 This is a Bayes problem.
P(B): prob. of blue=15%, P(G): prob. of green=85%, P(TB|B): prob. of testing
as Blue given it is blue=80%
P(B|TB)=P(TB|B)*P(B)/(P(TB|B)*P(B)+P(TB|G)*P(G))=0.41 |
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