[BruceZ]

[ QUOTE ]
Yea, but the post said test your logic - not application of Bayes Theoreom, although he does say probability question... I found it more interesting to attempt a logical (but not technically correct) solution, but you're right I failed since the post said "Odds" of him being sick, and not the test being right. It was fun nonetheless.

If he wanted a Bayes Theorem answer, why's this post here?

[/ QUOTE ]

This can be solved logically by persons who never heard of Bayes' theorem; however, if they don't come up with the same answer as Bayes' theorem, then their answer isn't logical; it's wrong.

The test is right 90% of the time. It doesn't have a 90% chance of being right when it pronounces someone sick. Once it pronounces someone sick, it only has a 1/12 or 8.3% chance of being right. When it pronounces someone well, it has almost a 99.9% chance of being right.

The fact that 1% of the people are sick is not irrelevant information; it's crucial for determining the odds that the test is right.