What the hell is a "false positive"? is that even possible?

Answer 1

All tests -- whether they are medical or statistical tests -- have a margin of error. There are false positives and false negatives. In statistics, these are called Type I and Type II errors.

http://en.wikipedia.org/wiki/Type_I_and_type_II_errors

Answer 2

A false positive is another way of saying ‘mistake’. As applied to the field of anti-virus programs, a false positive occurs when the program mistakenly flags an innocent file as being infected. This may seem harmless enough, but false positives can be a real nuisance.

Answer 3

A false positive is when you test positive for something that you don't have. It frequently happens with tuberculosis tests, pregnancy tests, and I have even heard of it happening with AIDS tests. A man was on anti-retro-viral medication for years before his doctors figured out he didn't have AIDS. Although medical science is advancing all the time, it is not perfect and many factors can affect the outcomes of diagnostic tests.

Answer 4

a false positive is when you say something has an effect on something even though it doesn't, or you say that a test yielded a positive (e.g. HIV) even though it really should read negative.

given this, a false negative is the opposite.

Answer 5

Let me give you a simple example of a false positive:

"Hey, there's Bob over there. ... No, wait, that's someone else. Never mind."

So, yes, that situation is possible.

Answer 6

A positive result that is incorrect. Like when a drug test incorrectly says you're a drug user.

Answer 7

It is a mistake, and yes mistakes are possible.