## Wednesday, February 15, 2006

### Cheney and Bayes

As you know, Dick Cheney has become the first U.S. vice-president after 201 years who has shot a person. Poor Harry Whittington, a 78-year-old Texas attorney and a supporter of the Bush-Cheney ticket, suffered a setback yesterday. As Prof. Charles M. has pointed out, the Los Angeles Times reports that
• a hospital spokesman said the chances that "one problematic birdshot" would migrate as it has toward Whittington's heart are "one in 99.99."
What does the figure mean? Yes, it is another Bayesian probability estimate. But what the conjectured probability actually is? It is either
• one in 100, i.e. 1 percent, expressed with a nonsensical accuracy
• or one in 10,000 i.e. 0.01 percent (so that the complement has a 99.99% probability)
You can choose any answer you want - 1 percent or 0.01 percent - but the actual answer is that under the exact conditions of Mr. Whittington including the doctors and spokespersonnel who don't know things like math, the probability was unfortunately 100 percent...

Every blog interprets this story according to its ideology. This blog first of all wishes Mr. Whittington strong nerves and good luck to become fit once again (he has a strong heart), and second of all we use it as an example of the unscientific nature of most Bayesian estimates.

#### 1 comment:

1. Lubos:

Have you seen what a bird shot looks like? It's not one single bullet but rather several hundred tiny metal pellets all shot out once. So what lodged into the face and chest of Mr. Whittington is not one single pellet, but rather about 300 of them. So the chance of one of the 300 pellets fall into the blood vessel and then travel to the heart is pretty high, if one single pellet has a 1% chance of doing it. This poor guy! Those pellets are too many and too small to be fetched out of his body. So he will have to live with all the bird pellets in his body for the rest of his life, however long that will be.

Although most would thought this is just an accident. A columnist doesn't think so and speculates the vice president intentionally shot the poor guy to send a warning to Scooter Libby It's too much a coincident that one day before the accident that the media reports Scooter admitted he did it under the instruction of a superior. Who could be a superior to a guy at Libby's position?

I also think an accident like this is extremely unlikely. Vice President is not an average citizen. He is the No.2 most powerful man on this planet and where ever he goes there is a big group of people by the name "secret service" surrounding him all the time. Any where he goes these people thoroughly comb an area half a mile in radius so if there is nail that he could step on, or if there is an insect that could bite him, they cleaned it out. The duty of these guys are to make sure the absolute safety of him and the people around him. Could Mr. Whittington show up unexpectedly and accidentally shot and kill the vice president? Not a chance. There must be some one accompanying him to make sure he doesn't do that, that same person would also be able to alert the vice president so he doesn't mis-fire, that is unless a mis-fire was intentional. So that possibility can not be ruled out.

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