Puzzler Answer: False Positive Puzzler

Ray: Hi, we're back. You're listening to Car Talk with us, Click and Clack, the Tappet Brothers, and we're here to talk about cars, car repair, and the answer to last week's Puzzler. This was the final Puzzler of the current Puzzler season.

Tom: So I should, like, savor this one? It's going to be a doozy, isn't it? A real season-ending splash. Is it going to be as good as the mango tree?

Ray: Jerk. All right. There's a rare disease sweeping through your town called . . . and the disease is called ACI, and it produces irreversible anal-cranial inversion. You may have noticed that my brother has it. Now, of all people exposed to ACI, only 0.1 percent actually contract it. OK?

Tom: Point one percent.

Ray: A tenth of a percent. OK?

Tom: Zero zero point one percent.

Ray: And if you catch it early, before the symptoms present, you can get treatment and maybe you can be cured. Fortunately, there's a diagnostic test which can detect ACI up to a year before the inversion occurs. So anyway, you go to your doctor and he administers the test, and it comes out positive.

Tom: Yeah?

Ray: And you say, "Oh, I'm done for." Then you're getting a little bit encouraged. You say, "Wait a minute, doc. Is this test 100 percent accurate? And he says, "Well, not really, but it's 95 percent accurate."

Tom: Ninety-five percent accurate.

Ray: All right? He says, in other words, 5 percent of the people who take the test will test positive but they don't really have it. The question is: What are the chances that you will actually have an irreversible anal-cranial inversion? And the answer is . . . have you worked out the math yet?

Tom: No, I haven't.

Ray: OK. Well, let's do it this way.

Tom: Go ahead.

Ray: What did I say the rate is? Point one percent?

Tom: Yeah.

Ray: OK. So .1 percent of the people who were exposed to it actually get it. That's one in a thousand. Is that right?

Tom: Mm-hmm.

Ray: Now, you tested positive and you figure, I'm done for, especially when you find out the test is 95 percent accurate. But if it is 95% accurate, that means if 1,000 people take the test, 50 people who don't have the disease will test positive, right?

Tom: Let me see now.

Ray: Well, if it's . . . let's go . . . let's go . . . let's make it simple for you.

Tom: Ninety-five percent, yes.

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 . . .

Tom: Yeah.

Ray: OK? And you're included in that thousand.

Tom: Yes.

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.

Tom: Correct.

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.

Tom: Sure.

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.

Tom: Yeah.

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.

Ray: Jeez.

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.

Ray: Wow. It could be a misspelling. Maybe our name is misspelled.

Tom: Exactly.

Ray: I mean we're supposed to be Tom and Ray Maggliozi.

Tom: Who would care?

Ray: I'm not.

Tom: I don't care. Anyway, Frank, for having your correct answer selected at random from the kayak full of correct answers that we got this week, you're going to get a $25 gift certificate to the Shameless Commerce Division at the Car Talk section of cars.com, with which you can get, like, a "Best of Car Talk" CD, which is guaranteed to bore your kids to sleep on those long summer road trips. You just stick this in the little CD player, and when all those kids are going, "Yaw, yaw, yaw,"‹right to sleep; knock them right out.

Ray: Well, we will not be having a new Puzzler in the third half of the show, but we will give you information, news, data on how you can get your Puzzler fix for the next few weeks . . . so in the meantime, if you want to call us about something else . . .

Tom: For how long is the vacation of the Puzzler?

Ray: It's being negotiated. That's all I can say. Anyway, the number is 888-CAR-TALK; that's 888-227-8255. Hello, you're on Car Talk. Ray: We're back. You're listening to Car Talk with us, Click and Clack, the Tappet Brothers, and we're here to discuss cars, car repair, and a little R & R.

Tom: Well, I haven't ranted for months.

Ray: Oh, that's what you meant by R & R?

Tom: R & R is Rant and Rave. And I have a rant, and you might agree with me on this one. You don't agree with me on anything, but you might agree with me on this one. I want to know whose idea was it to allow passing on the right? Now, how did that sneak into our lives? That is the worst idea. I can't think of any good reason to do it, and I can think of hundreds of reasons to not do it.

Ray: Well, I know who started it.

Tom: I want to know why do we do this and I want to stop it.

Ray: Oh, I know who started it.

Tom: I'm fed up with passing on the right.

Ray: Libby Owens Ford.

Tom: Libby Owens Ford? They wanted to sell more mirrors.

Ray: You got it. You got it.

Tom: You got it.

Ray: They make the mirrors, yeah.

Tom: They make the right-hand . . . you didn't need any mirror on the right-hand side of the car.

Ray: You didn't need no stinking mirror out there because there was nothing going on.

Tom: There was nothing going on there.

Ray: There was nothing happening there.

Tom: Exactly. What was there was was the breakdown lane. Now you've got wackos trying to pass you on all sides.

Ray: Worse than that, trucks, because they can't pass on the other side because . . .

Tom: They can't because they're not allowed in that lane.

Ray: They're not allowed in that line.

Tom: So they come zipping by you on the right-hand side. What is the purpose of being able to pass on the right? What's the upside of this? Why is it good?

Ray: Selling more mirrors.

Tom: Well, I would like to . . . we have to start a campaign.

Ray: Well, I don't know when it sneaked in. I honestly don't. I do remember one day many, many years ago hearing . . . I remember reading it in the paper, it's OK to pass on the right now.

Tom: And you said, "Huh?" Well, I can't remember when it happened.

Ray: It might have been 40 years ago.

Tom: No, it isn't that long ago.

Ray: Thirty-five.

Tom: It could be.

Ray: Well, we're about to find out.

Tom: Well, I want to find out. And, in fact, I want to know how other people feel about this. And I think I . . .

Ray: Oh, you'll hear.

Tom: I think it's time to do a little poll question on the Web site, which I will do tomorrow. And I'm asking people . . .

Ray: Well, you're really steamed out this, huh?

Tom: I want to ask people, how do you feel about this? Is it a good idea or a bad idea?

Ray: And should it be repealed?

Tom: And should it be repealed. And third, whose idea was it? There had to have been some compelling reason. I mean if someone says, "How about you can pass over the top from now on?"

Ray: It's coming.

Tom: You can drive up the backside and go right over the top. Someone will say, "I like it." Someone had to have said, "How come we cannot pass on the right? Let's do it." And someone said, "OK." Who was that?

Ray: Who was that person?

Tom: I want to know what was the reasoning he or she used.

Ray: Well, if you have any information regarding this matter, feel free to communicate with my brother through the usual channels, one, two, or seven. Hey, by the way, if you're saying to yourself, "Self, isn't this where those knuckleheads usually introduce the new Puzzler?" you would be right, but this being summer and we being, what?

Tom: Lazy.

Ray: There you go. The Puzzler is on summer vacation.

Tom: But if you're dying for a Puzzler, we're posting a classic Puzzler, classic, on our Web site every week while the Puzzler is away. Just go to the Car Talk section of cars.com and you'll be able to puzzle away the hours to your heart's content.

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