A factory manufactures surfboards. The factory manufactures the surfboards so accurately that only 1/1000 is ever bad. The boards are then checked by a machine to detect whether the board is good or bad. The machine checks with 99% accuracy. If Bob buys a surfboard which the machine detects as bad, what is the probability that the board really is bad?

Question

anonymous · Answer

Sorry the question is not in verbatim and I did come up with an answer. Just want to see what others get. @zepdrix @jim_thompson5910 @dan815 @primeralph

anonymous · Answer

@Mertsj @Zarkon @Directrix @karatechopper @nincompoop

primeralph · Answer

Bayes' Rule.

primeralph · Answer

|dw:1382507500721:dw|