Monthly Archives: November 2008

When does the sum of three numbers equal their product?

Mathematics Diary posted the following identity this morning. If a + b + c = π then tan(a) + tan(b) + tan(c) = tan(a) tan(b) tan(c). I’d never seen that before. It’s striking that the sum of three numbers would

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Posted in Math

Spell checking from Python

I needed to find a spell checker I could call from Python, so I did a Google search and ran across GNU aspell. I tried installing it but got contradictory warning messages: aspell not installed, aspell already installed, etc. Then

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Posted in Python

Checking your BlackBerry at a funeral

In a recent survey, 16% of those surveyed admitted to checking their BlackBerry at a funeral or memorial service. If even a funeral doesn’t make you ignore the ephemera of life for a few minutes to think about what’s important,

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Web 2.0 over dial-up

I’m borrowing an old Pentium III computer with a dial-up Internet connection. I haven’t used dial up in a long time and was surprised what a difference bandwidth makes. Many “Web 2.0″ sites are just painful to use. Some simply

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Posted in Computing

Distribution of adult heights

It is well known that adult male heights follow a normal (Gaussian) distribution. The same is true of adult female heights. But what does the distribution of heights look like for adults in general? You might be surprised. Assume heights

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Posted in Science, Statistics

How to put PDF properties in a LaTeX file

My previous post described how to put links in a PDF file generated from LaTeX. The hyperref package that lets you include links also lets you to set PDF document properties. I’ve been using Adobe Acrobat to do this after

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How to link to web pages from LaTeX-generated PDF

This has been on my to-do list for a while, but I finally found out how to embed hyperlinks in a PDF file generated from LaTeX. Short answer: put \usepackage{hyperref} in your header, and when you want to link to

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Posted in Uncategorized

Best voices in podcasting

Two of my favorite podcasters to listen to are Jon Udell and Mignon Fogarty. Related post: Favorite audio book narrators

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Posted in Uncategorized

Probability that a study result is true

Suppose a new study comes out saying a drug or a food or a habit lowers your risk of some disease. What is the probability that the study’s result is correct? Obviously this is a very important question, but one

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Posted in Clinical trials, Science, Statistics

Battling sharks

From The Unthinkable: Sharks kill an average of six people worldwide every year. Humans kill between 26 and 73 million sharks. This is not a battle humans are losing.

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I am not an operating system

I thought Apple’s I’m a Mac ad campaign was amusing, but I’m not impressed with Microsoft’s belated I’m a PC response. When Apple claimed that cool people use Macs, it was lame to respond that some PC users are cool

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Posted in Business

What it takes to make Paint.NET easy to install

Writing good installation programs is hard. It takes experience and forethought to imagine all the things that might happen on the client’s computer. Top notch programmers know that installers are critical to a user’s experience and put a lot of

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Posted in Graphics, Software development

The differences between bias, consistency, and efficiency

Sometimes code is easier to understand than abstract math. A few days ago I was having a hard time conveying bias, consistency, and efficiency in a statistics class. Writing some pseudo-code on the board seemed to help clear things up. Loops

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Posted in Python, Statistics

How many numbers are squares mod m

In a previous post, fast way to tell whether a number is a square, the question came up of how many integers are squares modulo an integer m. That is, for how many numbers y in the list 0, 1,

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Posted in Math, Python

Favorite audio book narrators

I have a long commute to work and so I’ve listened to a lot of recorded books. Here are my two favorite narrators for audio books. John McDonough, narrator of the Mitford series by Jan Karon. At Home in Mitford

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