The Straight Dope | The Straight Dope | Chicago Reader

# The Straight Dope

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I was perversely flipping through the Parade section of my Sunday newspaper when I stumbled upon Marilyn vos Savant's "Ask Marilyn" column. Even more perversely, I read it. It wasn't a total loss, though, because it appears she made another mistake, even worse than the one you pointed out in a very entertaining column a few months ago. Here's the question:

Suppose you're on a game show and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice?

ANSWER: Yes; you should switch. The first door has a one-third chance of winning, but second door has a two-thirds chance. Here's a good way to visualize what happened. Suppose there are a million doors, and you pick door No. 1. Then the host, who knows what's behind the doors and will always avoid the one with the prize, opens them all except door #777,777. You'd switch to that door pretty fast, wouldn't you?

Correct me if I'm wrong, Cecil, but aren't the odds equal for the remaining doors--one in two? --Michael Grice, Madison, Wisconsin

PS: If the questions she answers are any indication of the intellect of the general population, this country is in a lot of trouble.

This is getting ridiculous. You're perfectly correct. If there are three doors your chances of picking the right one are one in three. Knock one out of contention and the chances of either of the remaining doors being the right one are equal--one in two. This business about a million doors is a bit of pretzel logic that maybe only somebody with the world's highest IQ (according to Guinness, anyway) can properly appreciate. Parade's editors really ought to read the copy before they put it in the magazine.

Recently I was watching the season premiere of Against the Law (Fox TV) when a character mentioned that he had almost blown up his dad by sticking a potato up his car's tail pipe. Naturally I thought back to Beverly Hills Cop, where Eddie Murphy foiled the bumbling cops by putting a banana up their tail pipe. Does this really work? If so, why is it not more of a problem, especially in big cities where roving packs of thugs beat the tar out of people for fun? Seems like blowing up a car would have more comic value. Must the potato be cooked? Will any sizable fruit or vegetable (say, eggplant) do? I'd test on my own car, but it already dances on the thin line between minimal functioning and moribundity. --Patrick O'Malley, Alexandria, Virginia

Television writers are a plague. Stuffing a potato or anything short of a hand grenade up a car's tail pipe won't make it blow up. But it will keep the car from running. If exhaust gases can't escape, the engine can't "breathe," so it dies. Think about it: When a car's cylinders move up and down, they pull fuel and air in and push exhaust gases out. If the tail pipe is blocked, the exhaust can't go anywhere and stays put in the cylinders, preventing fresh stuff from entering. No fresh stuff = no combustion = no transportation. It also means no unintended explosions, which maybe is why street gangs haven't picked up on it. Thank God.

THE NEWS: NOT THAT WEIRD

You are correct (as usual) [September 21, on gerbil stuffing]. I made a transcribing error. --Chuck Shepherd, Deadfromtheneckup, Inc., Washington, D.C.

Confession is good for the soul, Chuck. But let me get this straight: are you saying that including "a live, shaved, declawed gerbil" on a list of "items recovered from the rectums of patients" was a transcribing error? If so, you really gotta work on that handwriting.

Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.