Ross Ikaha (via Xi'an -- thanks ;) ) gives a nice example to show why R is basically impossible to optimize: __ f = function() { __ if (runif(1) __ 0.5) { __ x = 10 __ } __ x __ } x in the last expression could be a local or a global, and this won't be known until runtime! That's pretty good. I wonder if ... [Read more...]

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Tamino over at  Open Mind has a new post detailing his approach for calculating temperature averages. See his post here. His method is based on the Berkeley method as he notes and he uses it primarily for calculating regional or local temperature averages. Read his post for the math details ... [Read more...]

I've been playing around with the rgl package in the last week, as part of an ongoing quest to come up with nice-looking (but more importantly, useful) data vizualisations. It's a nice little package, and once you've run through the excell... [Read more...]

If a particular prediction comes true, how surprised should we be? The prediction The page that sparked my curiosity tells of a prediction made a year ago that the S&P 500 would beat its historic high by the end of 2011.  It says that at the point the prediction was made, ... [Read more...]

As a fact-based blog, the posts here contain very often diagrams and data tables. To enable you to reproduce the results and insights, I include the computations as computer code.Most blogposts I write are markdown text combined (or weaved) with computer code written in the R language. I created ... [Read more...]

Today a lot of great mails arrived at my inbox. In one of them I was reading I’ve just added your feed to the site. Where did this mail come from? The sender of the email was Tal Galili. He is a researcher in BioStatistics at the Tel Aviv ... [Read more...]

In this post, I give an outline for those interested in migrating from using SPSS and Excel for data processing/analysis …Continue reading » [Read more...]

  I wrote before about using heatmap tables to combine the strengths of tables and graphics for nominal data. Here is a neat approach using Sweave and latex to produce an effect like in the picture. This latex code is self-contain... [Read more...]

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So the other day’s experiment with the Failed States Index and the Polity Data didn’t yield the linear trend I had originally expected.  After all, the two measure fundamentally distinct things.  But perhaps there’s another dataset which will match linearly.  The same people who made polity also ... [Read more...]

Last year Wikipedia rolled out a pilot program to use Wikipedia article creation as an assignment in the classroom. Students wrote articles on a topic area and rather than turning them into a professor and forgetting about it they upload it to Wikipedia and expose it to readers around the ... [Read more...]

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Just as scientists should never really have to think much about statistics, I feel that, in an ideal world, statisticians would never have to worry about computing. In the real world, though, we have to spend a lot of time building our own tools.It would be great if we ... [Read more...]

Hadley Wickham gave a Google Tech Talk a couple weeks back titled Engineering Data Analysis (with R and ggplot2). These are my notes. The data analysis cycle is to iteratively transform, visualize and model. Leading into the cycle is data access an... [Read more...]

In the next few days we’ll be changing the format of the blog and moving it to a new server. If you have difficulty posting comments, just wait and post them in a few days when all should be working well. (But if you can post a comment, go ... [Read more...]

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Yesterday's New York Times includes a great article on the failure of some genetic tests for cancer detection, and the flaws in the research that led to them. The article features quotes from Keith Baggerly of MD Anderson Cancer Center, and includes a photo of him and colleague Kevin Coombes ... [Read more...]

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