Thursday, April 27, 2006

A Hung Jury is Bad, But....

I was lecturing on Condorcet's "Jury Theorem."

It bears on many problems in political theory, but my point that day was that a group of schlubs (chance of being correct: 0.51) might be "smarter", if we require unanimity, than one well trained judge (chance of being correct: .95). The reason exploits statistical independence: the probabilities of 12 jurors all (independently) being wrong is very small. So a unanimous guilty verdict of people off the street is better than one smart judge. The chance of 12 .51 folks all, separately, being wrong is [(0.49)^12]=.0002. So, *if* the jury is unanimous in favor of one outcome, the chance that they are correct is .9998.

A student asked, "But what if the jury isn't unanimous?"

I said, "That may not be a bad thing; it means you aren't sure. And in our system, 'not sure' means NOT GUILTY."

A pause. Then is where I made my misstep. I wanted to compare juries with judges.

"If the jury is NOT uanimous, that's a hung jury. You know what to do with a hung jury. Either a misstrial, or just call it not guilty. BUT, what would you do with a hung judge?" I stopped, horrified; the students stared.

Then, a young woman at the back yelled: "Marry him!"

It took several minutes for order to be restored. And I still haven't quite recovered.

Men are Unnecessary III

The boys and I go out to our "man property." 35 acres of pine forest in Chatham County, south of Pittsboro.

We take provisions: many weapons, a wheelbarrow full of ammunition, 125 cc Suzuki dirt bike, bushels of Doritos, more sandwiches than anyone could ever want, umbrella, folding chairs....and we set up camp.

Then we work on the baseball field that we are building ("If you build it....nerds will come.") Field is shaping up well, will soon be ready for practice.

But the real reason is to do empirical experiments, and record the results. Our most recent experiment was to try to figure out how quickly you could take down a standing, but dead, 4 inch diameter pine tree with shotgun fire by firing at the base from ten yards. Two variables: steel shot/lead shot, and standard/magnum loads.

We kept good data, but the results were so predictable that it is only worth summarizing. No apparent difference in shot type, but magnum load reduces shots required between 30% and 50%. In terms of scale, the MOST it ever took was ten shots, and that was Monty Python ("I'm not dead yet!") tree that we shouldn't have included in the sample.

We also fired several boxes of 22 short shells. We just got a Ruger 10/22, and I have to say it is a whole of fun. We have two 30-round aftermarket banana clips, and the little Ruger is quite sturdy in terms of not jamming even if you fire as fast as you can pull the trigger. It took us a long time to get the scope sighted in, but with the scope set up correctly the gun is as accurate as you could possibly want.

I nailed a toilet seat to a 2x4 frame, over a shallow pit. These latrine facilities are not exactly appropriate for female use, not because they don't work (gravity is EVERYWHERE, I tell you!), but because the open air setting is not something most women would want to try out. For my own view, let me say there is something special about answering nature's call on a small hilltop, and being able to see at least 1/4 mile in all directions, as a gentle breeze blows through your private parts. You sit and think to yourself: MY land! This is MY land! And I am heavily armed! Or, I will be as soon as I get off this toilet seat.

Wednesday, April 26, 2006

Bad times

Sorry to be away so much. Very hard month.

But, on the plus side:

1. My good friend Stephen Wilkinson got tenure at Duke!

UPDATE: I misspelled Steven's name. My only excuse is that I was assuming he was using the old Brit trick of adding useless letters words, such as labour or colour. That way their books are longer with no additional effort. Anyway, sorry about that, Steffan!

2. My good friend Scott de Marchi got tenure at Duke!

3. Classes are over!

4. The Department finished its response to the external review report, and sent the response up to the Allen building.** This took days and days of "work," meaning the thing you do when you are too stupid to write anything useful or interesting. (UPDATE: Yes, I am talking about myself being too stupid to write anything useful or interesting. Being chair is like a lobotomy, except there is no scar and it pays better).

5. Neither of my sons play lacrosse.*

So, I'm feeling blessed.

(*UPDATE: earlier version said "plays." Sorry)

(**Quick: is refering to the university administration as "The Allen Building" an example of (choose all that apply)? :

a. Onomatepoeia
b. Synecdoche
c. Metonymy
d. Irony
e. Pomposity )

(UPDATE: actual pix of Wilkinson and de Marchi added after original post. Uncanny, right?)