I am in a fantasy hockey league for the first time this seasons and I wanted to use R to analyze players.  Since I am relatively new to R, I am quite certain this code could be improved.  The code below is functional, however, and while this isn’t my ... [Read more...]

In this post I publish a PDF document titled “A collection of tips for R in Finance”. It is a basic 5 page introduction to R in finances by Arnaud Amsellem (linked in profile). The article offers tips related to the following points: Code Editor Organizing R code Update packages Getting ... [Read more...]

...a continuing journey through Using R for Introductory Statistics, by John Verzani. Simple linear regression Linear regression is a kooky term for fitting a line to some data. This odd bit of terminology can be blamed on Sir Francis Galton, a proli... [Read more...]

At any R Q&A site, you’ll frequently see an exchange like this one: Q: How can I use a loop to [...insert task here...] ? A: Don’t. Use one of the apply functions. So, what are these wondrous apply functions and how do they work? I think the ... [Read more...]

The (excellent!) LearnR blog had a post today about making a rose plot in ggplot2. Following today’s announcement, by Ian Fellows, regarding the release of the new version of Deducer (0.4) offering a strong support for ggplot2 using a GUI plot builder, Ian also sent an e-mail where he shows ... [Read more...]

Ian fellows, a hard working contributer to the R community (and a cool guy), has announced today the release of Deducer (0.4) to CRAN (scheduled to update in the next day or so). This major update also includes the release of a new plug-in package (DeducerExtras), containing additional dialogs and functionality. ... [Read more...]

There are a lot of great references on the web on how to levarage LaTeX for reporting and presentations (beamer), but as someone who is completely new to R and reproducible research, I was having a pretty hard time figuring out simply what to do (what tools, where do you ... [Read more...]

As promised a few posts ago, another demonstration of the excellent biomaRt package, this time in conjunction with GenomeGraphs. Here’s what we’re going to do: Grab some public microarray data Normalise and get a list of the most differentially-expressed probesets Use biomaRt to fetch the genes associated with ... [Read more...]

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Repeated measures ANOVA is a common task for the data analyst. There are (at least) two ways of performing “repeated measures ANOVA” using R but none is really trivial, and each way has it’s own complication/pitfalls (explanation/solution to which I was usually able to find through searching ... [Read more...]

When analyzing a questionnaire, one often wants to view the correlation between two or more Likert questionnaire item’s (for example: two ordered categorical vectors ranging from 1 to 5). When dealing with several such Likert variable’s, a clear presentation of all the pairwise relation’s between our variable can be ... [Read more...]

Major credit card issuing networks (including Visa, MasterCard, Discover, and American Express) allow simple credit card number validation using the Luhn Algorithm (also called the “modulus 10″ or “mod 10″ algorithm). The following code demonstrates an implementation in SAS. The code also validates the credit card number by length and by checking ... [Read more...]

Conditional inference trees (ctree) in package party allows weighting which is useful when one classification outcome is more important than another. Useful examples are not difficult to imagine: in a marketing direct mailing, a false positive (non-res... [Read more...]

Patrick Burns just posted to the mailing list the following massage: There is now a document called “Some hints for the R beginner” whose purpose is to get people up and running with R as quickly as possible. Direct access to it is: http://www.burns-stat.com/pages/Tutor/hints_... [Read more...]

Nathan Yau of Flowingdata put up a challenge earlier today to improve upon a graph showing government spending as a percentage of GDP, published in the Economist. The underlying data wasn’t available. So I put on my graph-to-numbers glasses on and pulled out some data. Here it is in ... [Read more...]

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This tutorial covers profiling of Linux servers using open-source tools such as "iostat", "oprofile" and "blktrace". Both processor-bound and I/O-bound cases are covered, and the emphasis is on tools that provide visual displays of relevant metrics. Li... [Read more...]

Here is a HD version of a video tutorial on web development with R, a lecture that was given by Jeroen Ooms (the guy who made A web application for R’s ggplot2). This talk was given at the Bay Area UseR Group meeting on R-Powered Web Apps. You can ... [Read more...]