Wednesday, October 26, 2005

The Astros, Phil Garner and Regression to the Mean

Disclaimer: I remain an Astro's fan.
Out of frustration, Phil Garner of the Astros has gotten a little angry about his team's seeming inability to move runners from scoring position to home plate. Frustration is an ugly thing. Not as ugly and as silly as portrayed by Sport Illustrated's Tom Verducci here, but pretty ugly. About 2 am with the Astros pitching some guy who could not find the plate with a seeing eye dog, I was a little frustrated myself. However, it is not for nothing I toiled for several minutes in my beer-soaked college and grad school days on statistics and probabilities - it was so I could grasp batting averages, ERAs and all that other stuff that had to do with earning a living, too.

And so, at the crack of dawn, I began to ponder why we (Phil and I) would expect a lifetime .250 hitter who was batting .500 for the series to continue hitting at a torrid pace instead of reverting to his normal batting average and suddenly not being able to hit a lick until his average dropped back to .250? And the answer is that we had forgotten (in our fevered hopes that reality wouldn't pound on our baseball fantasy of the Astros winning the World Series) the concept of Regression to the Mean. Or, as bright people say,
Regression to the mean is a technical term in probability and statistics. It means that, left to themselves, things tend to return to normal, whatever that is.
Thereby hangs the tale of one Astro, playing centerfield during this series, named Willy Taveras. Mr. Taveras hit .270 during the regular season. One can assume that he will hit .270 during the World Series. Now, going into last night's game, he was hitting over .400 (now, after an awful night, down to .308). Regression to the Mean suggests that he will not continue at that pace, but stop getting hits until he reaches his mean, all other things being equal. Perhaps the quality of the White Sox pitching is driving averages down, but many of the Astros are hitting (in the Series) well below their regular season averages. Biggio (WS .214, Reg .264), Ensberg (WS .143, Reg .283), Lane (WS .214, Reg .267), Everitt (WS .083, Reg .248), Lamb (WS .125, Reg .236), Burke (WS .000, Reg .248). Only Berkman seems to be feasting on Chicago pitching (WS .417, Reg .293).

No wonder Garner is frustrated!

Now, it may not happen, but I would hope some of the Astros will begin to regress to their normal averages (which would mean a hit fest)-- really soon, like tonight!

If not, they won't get another chance.

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