Monday, December 9, 2013

Don't feed the men in the gray suits

Shortly after I came to The Maui News in 1987, we had a story about a newlywed couple who stopped on the road to Hana to take pictures at a waterfall. Just like in the Charles Addams cartoon, the husband -- trying not to "cut off his wife's head" -- stepped back and over a cliff.

Details have faded, but as I recall he was killed.

A few weeks later, darned if it didn't happen again with another newlywed couple. This time, as I recall, the groom died and the bride, trying to climb down to him, fell and broke most of her bones but lived.

Does this happen all the time? I asked myself. But from that day to this, it has never happened again.

I bring up this ancient history because there have been two fatal shark attacks around Maui in the last few weeks. But if a tourist asks, does this happen all the time? the answer is no. There hadn't been a fatal shark bite anywhere in Hawaii since 2004.

That there were two, close together in time and space, is just a matter of the Law of Small Numbers. If you have a sample of three events over time X, then for sure at least twice as many will occur in one period as in the other. Or maybe it will be 3:0.

Of such arise panics of cancer clusters, shark attacks, tornadoes and a slew of non-events.

So I was surprised and pleased to read Rep. Kaniela Ing's blog post on sharks. He does not explicitly invoke the Law of Small Numbers but clearly he understands how it works.

While the entire world averages about four shark attack fatalities a year, South Maui has had two in 2013 alone, accounting for both of Hawaii’s only shark attack fatalities since 2004.
The real curiosity is in the menu. Of the first 100 documented shark attacks in Hawaii, not one involved a tourist. Now about half of them do.




1 comment:

  1. That there were two, close together in time and space, is just a matter of the Law of Small Numbers.

    No, it is randomness in action.

    People expect random events to be evenly distributed over time. But if they were, they wouldn't be random.

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