CowPunk wrote:
Let's assume that the labs and their tests are 99% accurate.

The UCI did around 12000 tests last year, and about 380 came back
positive. These are just rough numbers off the top of my head.
It worked out to around 3.8% of all tests came back positive.

So, if you take that 99% accuracy number and apply it,
you end up with roughly 1 out of 3 positives due to bad testing.


It's been a million years since I took a probability class so I must
have just confused myself. Someone please straighten me out here.

If the probability of a false positive is .01 then the probability of
both A and B samples receiving a false positives is .01 * .01 = .0001.
I think that means that ~1.2 times a year someone innocent should fail
both the A and B sample despite being clean.

That's got to be wrong.