A few months ago I decided to apply word frequency analysis ideas to R code. My idea was simple: the functions that one should invest the most effort into learning are precisely those functions that are used most frequently in real world code. In fact, this simple idea can be ... [Read more...]

Instead of the factor() function which usually applies after defining a vector there’s the gl() base function to do this in one step, eg freq [Read more...]

I’m looking at ways to provide access to R via a web application. First rule: see what’s available first, before you reinvent the wheel. It’s not pretty. From the R Web Interfaces FAQ: Software Brief notes Rweb Page last updated 1999. Of the 3 example links on the page ... [Read more...]

…in R of course! There is a handy function to do those calculations. Normally (ahh!) you might resolve to a symbolic calculation package (Maple,Mathematica etc.)  but that is not the situation any more. The calculations are done with the mnormt package. Relevant functions exist in other packages as well (... [Read more...]

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This article is quick concrete example of how to use the techniques from Survive R to lower the steepness of The R Project for Statistical Computing‘s learning curve (so an apology to all readers who are not interested in R). What follows is for people who already use R ... [Read more...]

Estimating a proportion at first looks elementary. Hail to aymptotics, right? Well, initially it might seem efficient to iuse the fact that . In other words the classical confidence interval relies on the inversion of Wald’s test. A function to ease the computation is the following (not really needed!). waldci [Read more...]

Introduction As promised on Thursday, here’s my second pass at a statistical analysis of Canabalt scores. There are some useful results I’ll present right at the start, and then there are some results that are more or less worthless, except that working through my own mistakes helped me ... [Read more...]

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At the office today, I got into a discussion with two of my fellow graduate students about the distribution of scores you can get while playing Canabalt. Because (1) the layout of the levels in the game is fully randomized and (2) the difficulty of certain actions (specifically jumping through windows) is ... [Read more...]

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Every year, I single out what I think are the Top Five open source projects. This year, there's only one hold-over from previous years, and it's likely that I'm just going to give it a Lifetime Achievement Award and pick five others next year. 5. NetBe... [Read more...]

Named rjson, appropriately. It’s quite basic just now, but contains methods for interconversion between R objects and JSON. Something like this: __ library(rjson) __ data json json [1] "{\"a\":1,\"b\":2,\"c\":3}" __ cat(json, file="data.json") Use cases? I wonder if RApache could be used to build an API that serves ... [Read more...]

Well testing a bunch of samples for the largest population mean isn’t that common yet a simple test is at hand. Under the obvious title “The rank sum maximum test for the largest K population means” the test relies on the calculation of the sum of ranks under the ... [Read more...]

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This post will eventually grow to hold a wide list of books on statistics (e-books, pdf books and so on) that are available for free download.  But for now we’ll start off with just one several books: The Elements of Statistical Learning written by Trevor Hastie, Robert Tibshirani and ... [Read more...]

Welcome to part two of the Introduction to The R Project for Statistical Computing tutorial. If you missed part one, it can be found here. In this segment, we will explore the following topics.Importing DataVariablesWorkspace FilesConsole FilesFinding ... [Read more...]

R is a free, cross-platform, open-source statistical analysis language and program. It is also an alternative to expensive commercial statistics software such as SPSS. The environment for R differs from the typical point and click interface found in mo... [Read more...]

R is a great tool with lots of resources for genetics, genome-wide association studies, and many other biological applications.  We've covered several places to find help in R in the past, but if you're still apprehensive about diving into R's command-line interface, fear not.  The R commander is a graphical ... [Read more...]