Monthly Archives: June 2009

Privacy

From Digital Barbarism by Mark Helprin: I do not want my life history in the hands of either J. Edgar Hoover or Walt Disney, thank you very much.

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Incredibly simple approximation

Suppose you need to find the slope of a line through a set of data. You can get a surprisingly good approximation by simply fitting a line to the first and last points. This is known as “Bancroft’s rule.” It

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Posted in Statistics

Eclectic links

Food Espresso cheat sheet Too much salt, sugar, and fat Software development Hanselminutes interview with Michael Feathers How SQLite is tested (including 45 million lines of test code) Math/Stat Math Teachers at Play blog carnival #10 Defining values of statisticians

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Probability mistake can give a good approximation

If you run into someone on the street, the probability that the other person shares your birthday is 1/365. If you run into five people, the probability that at least one of them shares your birthday is 5/365, right? The

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Posted in Math

Optical illusion, mathematical illusion

Someone sent me a link to an optical illusion while I was working on a math problem. The two things turned out to be related. In the image below, what look like blues spiral and green spirals are actually exactly

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Posted in Graphics, Math

John Tukey’s median of medians

Yesterday I got an email from Jestin Abraham asking a question about Tukey’s “median of medians” paper from 1978. (The full title is “The Ninther, a Technique for Low-Effort Robust (Resistant) Location in Large Samples.”) Jestin thought I might be

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Posted in Statistics

Dan Bricklin interview

Dan Bricklin is best known for creating VisiCalc along with Bob Frankston in 1979. Since that time he has been active as a software developer and entrepreneur. His new book is Bricklin on Technology. I quoted Dan Bricklin in a

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Posted in Business, Software development

Conservation of attractive profits

Tim O’Reilly talked about the “law of conservation of attractive profits” in a recent interview on the FLOSS Weekly podcast. Clayton Christensen explained this law in an HBR report in 2004. It says that when one thing becomes modular and

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Posted in Business

The Endeavour is now a podcast

This blog is now available as a podcast. I’m experimenting with the Odiogo service to automatically create an audio version of the blog text. The speech quality is surprisingly good, much better than the Windows speech synthesizer. You can listen

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Miscellaneous links

What it’s like to run a marathon in space. Mathematical artwork from Chris Henden: finite projective plane balanced incomplete block design binomial expansion (A lot of mathematical art is gimmicky. Interesting, but not beautiful. Chris Henden’s work is beautiful. I

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Backup and recovery

Paul Randal had the following to say about database backup and recovery in his interview with .NET Rocks. Don’t ever, ever plan a backup strategy. Plan a restore strategy. The point of a backup is to be able to restore

Posted in Computing

The most subtle of the seven deadly sins

Six of the seven deadly sins are easy to define, but one is more subtle. The seven deadly sins are lust gluttony greed sloth wrath envy pride. Sloth is the subtle one. I discovered recently that I didn’t know what

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Questioning the Hawthorne effect

The Hawthorne effect is the idea that people perform better when they’re being studied. The name comes from studies conducted at Western Electric’s Hawthorne Works facility. Increased lighting improved productivity in the plant. Later, lowering the lighting also increased productivity.

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Posted in Business, Science

The Unix Programming Environment

Joel Spolsky recommends the following books to self-taught programmers who apply to his company and need to fill in some gaps in their training. Structure and Interpretation of Computer Programs The C Programming Language The Unix Programming Environment Introduction to

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Posted in Computing

Upcoming Y2K-like problems

The world’s computer systems kept working on January 1, 2000 thanks to billions of dollars spent on fixing old software. Two wrong conclusions to draw from Y2K are The programmers responsible for Y2K bugs were losers. That’s all behind us

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Posted in Computing