Alarming decisions

September 16, 2011 · 6 comments

You’re checking in at a hotel. Two rooms are available, each with a different fire alarm. The manager tells you that if there’s a fire, you have a 2 percent chance of dying in Room 1. In Room 2, you only have a 1 percent chance.

But

Room 2′s alarm is squirrelly. Its wiring may cause an electrical fire, which increases your chance of dying in Room 2 by an additional 0.01 percent.

Which room do you choose?

{ 6 comments… read them below or add one }

Bob Patterson September 16, 2011 at 12:04 pm

I’d choose the room with the better view or the farthest from the ice machine. Then open a beer enjoy Monday night football and let the actuaries down the fret about the numbers.

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Dr. Drang September 16, 2011 at 1:30 pm

I have to say I hate this problem, and I agree with the commenters at Actuary Info who say that taking Room 1 could be a rational response.

The problem is that the 2% and 1% risks given in the first paragraph are clearly conditional probabilities: “if there’s a fire…” But the 0.01% probability in the second paragraph is associated with the alarm *causing* a fire. As a practical matter, that can’t be a probability conditional on the event of a fire, no matter what the intent of the problem statement was.

I get the point about irrational response to betrayal—there are similar studies showing that people accept higher risk in situations where they feel more in control—but the particulars of this example were, I think, poorly chosen.

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Eddie September 16, 2011 at 4:59 pm

You pass.

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Dr. Drang September 16, 2011 at 8:33 pm

Yes, but Mr. Patterson gets an A+.

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Eddie September 16, 2011 at 9:08 pm

True. Plus, most actuaries would continue arguing the materiality of the conditional probability while the hotel burned around them.

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Deverill September 22, 2011 at 9:41 am

I would have to ask myself why they don’t change the detectors in all the rooms to the better quality (1%) and yet not defective alarms and then go down the road to another hotel. :)

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