Wednesday, June 30, 2010

How Mariano Rivera Dominates Hitters



Here is an excellent animation from the New York Times showing how Mariano Rivera has been such a dominant closer in baseball. It shows how his similar deliveries result in drastically different ball placement at the plate. They analyzed nearly 1300 of his pitches over the 2009 season. The scatterplots show the location of the ball as it goes over the plate. He is amazingly adept at keeping the ball on the corners and away from the middle of the plate, where a hitter would have the best contact.

Tuesday, June 29, 2010

The First Published Random Walk?


According to Alex Bellos in his new book "Here's Looking at Euclid", this is the world's first graph of a random walk, published by John Venn in his book "The Logic of Chance" in 1888. Venn produces this path using the digits from 0 to 7 from the first 707 digits of π. Venn writes,
"Of these, after omitting 8 and 9, there remain 568; the diagram represents the course traced out by following the direction of these as the clue to our path. Many of the steps have of course been taken in opposite directions twice or oftener. The result seems to me to furnish a very fair graphical indication of randomness. I have compared it with corresponding paths furnished by rows of figures taken from logarithmic tables, and in other ways, and find the results to be much the same."
Here are the directions Venn uses and the results from the first ten decimal digits.

Monday, June 28, 2010


This is an pair of automatic entry doors to the terminal at Dulles airport outside of Washington, DC. Although the doors open automatically as you approach, passengers pushing luggage carts ahead of them hit the bottom edge of the doors when they open too slowly. This leaves a distinctive wear pattern on each door. Most carts hit the same spot, some cause wear a little higher, some cause wear a little lower. This could be from different cart heights or different loads on the carts or from the slight dents in the door from the repeated bumpings, causing the carts to hit more off the center target. A bell-shaped frequency distribution is left behind. Most wear in the center less towards the extremes.

Friday, June 4, 2010


Not so much an image this time, but a quote I like from the book "The Great Influenza" by John M. Barry that I am currently reading.

"To be a scientist requires not only intelligence and curiosity, but passion, patience, creativity, self-sufficiency, and courage. It is not the courage to venture into the unknown. It is the courage to accept -- indeed, embrace -- uncertainty."