Explain 1 in 10,000

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Explain 1 in 10,000
Message posted by David B. (via 65.0.77.18) on September 3, 2001 at 8:52 AM (ET)

It's easy to explain 1 in 2: "flip a coin -- about half the time it will come up heads." But how to you explain 1 in 10,000? Saying "you'll trip once every 10,000 steps" (as an example) isn't quite correct, right? Better example?

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Re: Explain 1 in 10,000
Message posted by Tomi Owens (via 154.32.143.126) on September 3, 2001 at 8:59 AM (ET)

"1 in 10,000" is a very rare event and people are not good at dealing with rare events - mainly because they don't meet them very frequently (by definition).

Re: Explain 1 in 10,000
Message posted by Tomi Owens (via 154.32.143.126) on September 3, 2001 at 9:06 AM (ET)

One way is to give the probability in terms of a very large number.

1 in 10,000 is the same as 100 in 1,000,000, so try:

"If you have 1 million dollar bills, 100 of these are likely to be fake."

Or try using the population of your country as a denominator:

"A 1 in 10,000 probability of a disease occurring would mean that in the whole UK (pop 60 million) there would be about 6,000 people with the disease."

Another way of looking at is to use the coin argument you used first but extend it. Since 10,000 is 2^13.29 you could say:

"Imagine tossing a fair coin 13 times and it coming up heads each time. That's not very likely, is it? Well, a 1 in 10,000 chance is even more unlikely than that."

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