My greatest pleasures in mathematics come from observing--and here, listening to--the interplay of simple and complex. With a few axioms and definitions you can create surprising worlds, and in what seems like a mess you can find beautiful regularities. It's damn sexy, frankly. Here, I use a simple recursive equation ... [Read more...]

We run an occasional series here on Revolutions called The R-Files, in which we profile members of the R community. Our intention with this series is to call out noteworthy work being done for open-source R and popular CRAN packages, and shine a light on some of the noteworthy individuals ... [Read more...]

TOMACS (ACM Transactions on Modeling and Computer Simulation) is launching a call for paper submission. The special topic is Monte Carlo Methods in Statistics and Arnaud Doucet and myself are the special issue editors. Here are the details.: Over the last two decades Monte Carlo methods have attracted much attention ... [Read more...]

Rapidminer is a cool toy to play with machine-learning/data-mining algorithms and it can interface with R. However, it was a bit problematic for me to get the R extension working properly on Mac OS X Leopard for R 2.11. Here is what works for me at the... [Read more...]

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Abhijit over at Stat Bandit posted some nice code for making forest plots using ggplot2 in R. You see these lots of times in meta-analyses, or as seen in the BioVU demonstration paper. The idea is simple - on the x-axis you have the odds ratio (or what... [Read more...]

As most readers are probably aware, the free IDE for R, called RStudio, was recently released for general use and it immediately made huge waves within the R community. IDE stands for Integrated Development Environment. IDEs typically provides a rich set tools developing in some target language. For standard programming ... [Read more...]

It is common to look at best time at the Marathon. Or perhaps the distribution of the top100, as done by John Myles White on his blog here (data can be found there), as the graph below, with the density of the time for the first 100 men (in blue) a... [Read more...]

A standard idea in extreme value theory (see e.g. here, in French unfortunately) is that to estimate the 99.5% quantile (say), we just need to estimate a quantile of level 95% for observations exceeding the 90% quantile. In extreme value theory,... [Read more...]

A quick method to enumerate the printable ascii characters with their hex & decimal values.The following code relies on taking the "raw" value of a base 10 int (this gives a hex value), and then using the builtin function rawToChar, which gives a character. You can of course change the range (... [Read more...]

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Google today announced a Data Visualization Challenge that is well suited to the graphical capabilities of R. The goal is to visualize the US Federal budget from the point of view of the taxes an individual pays. The data are available from whatwepayfor.com -- their FAQ gives details about ... [Read more...]

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Two posts ago I mentioned the age-earnings profile but did not provide a regression of log earnings on wage. I also offered, without evidence, that fitting a simple linear regression would be inappropriate. How do I know that? How could … Continue reading → [Read more...]

In my previous post I showed you how to randomly split up a dataset into training and testing datasets. (Thanks to all those who emailed me or left comments letting me know that this could be done using other means. As things go with R, it's sometimes ... [Read more...]

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                      If you think that R is The EnvironmentForStatisticalAnalysisAndGraphics but you do not think that Vim is The Editor for text files you might want to have a look at R Studio. It works on Windows, MacOS and Linux. I tried it out on my Ubuntu [...] [Read more...]

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Exercise 3 is about multivariate linear regression. First part is about finding a good learning rate (alpha) and 2nd part is about implementing linear regression using normal equations instead of the gradient descent algorithm. Data As usual hosted in google docs: mydata = read.csv("http://spreadsheets.google.com/pub?key=0AnypY27... [Read more...]