False Positive Puzzler
RAY: Let's say if it was 100 people who took it . . . let's start here, Tommy, 100 people.
TOM: No, I'm with you. I was on a different track. I'm with you. Fifty people who take the test will test positive and yet they will not have it.
RAY: Right. So out of 1,000 people who take it . . .
RAY: OK? And you're included in that thousand.
RAY: OK? Fifty-one people out of 1,000 are going to test positive. One of those people is going to have it and 50 are not going to have it.
RAY: So your chances of actually having it, even though you tested positive, are one in 51, or a little less than 2 percent.
TOM: Two percent.
RAY: And that's just another way that statistics can fool and lie to you and make you jump, suicidal . . . and jump off a bridge because you tested positive.
RAY: And the test is 95 percent accurate.
TOM: It sounds so good. So you're saying 2 percent is pretty small.
RAY: Well, I mean, your chances of having it are twentyfold greater than just a person off the street.
TOM: Exactly. Right.
RAY: You know?
TOM: Which is only .1 percent.
RAY: By testing positive.
RAY: But it's still . . . I mean, considering how dire the news was just a moment ago . . .
TOM: It's now down to 2 percent.
RAY: It's down to 2 percent. I mean . . .
TOM: Don't even pay any attention to it.
RAY: You've got a 2 percent chance of being hit by Skylab. Is that still up there? Anyway, who's our winner?
TOM: The winner is . . . no kidding.
TOM: What are the chances of this? Wow. The winner is a guy named‹and I'm going to pronounce it correctly for us‹Frank Maggliozi, or, as some people would say, Maggliozi from Rye Brook, New York. Wow.
[ Car Talk Puzzler ]