2009

Long R, Short Excel

October 29, 2009 | Milk Trader

R is very speedy statistical package that's like an F-18A Hornet, versus Excel which is like a paper airplane. R is professional sports, Excel is Pop Warner. R is Mona Lisa, Excel is stick figures. R is ... okay, you get the idea. I'm long R, and short...
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Kicking Ass with plyr

October 29, 2009 | JD Long

Tonight (October 29, 2009) at 5:30 PM is the Chicago R meetup at Jaks tap. Here’s more info.  I’ll be making a presentation based on my earlier blog post about plyr. The presentation will only be 8 minutes long so I’ve had to pick and choose my info carefully. OK, who ... [Read more...]

Go long on close and sell on open

October 29, 2009 | kafka

I found a description of supposed to be profitable strategy on Bloomberg. The strategy is simple – buy S&P500 index on close and sell it on next day open. So, I tested this claim and got nice P/L curve: Yes, since 1993 this strategy has generated the profit __300%. But, neither ... [Read more...]

Bioconductor 2.5 is out

October 29, 2009 | Paolo

For all bioinformaticians and R users out there: the Bioconductor project  for the analysis and comprehension of genomic data is out! A lot of interesting new stuff! See the full announcement here.
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R 2.10.0 is Out!

October 26, 2009 | Paolo

The new R 2.10.0 is out! Get it from here. If you like take a look at these posts for some miscellaneous advices to make the upgrade easier. Fell free to contribute with suggestions about how to upgrade your R installation.
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Free statistics e-books for download

October 25, 2009 | Tal Galili

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...]

Example 7.16: assess robustness of permutation test to violations of exchangeability assumption

October 24, 2009 | Nick Horton

Permutation tests (section 2.4.3) are a form of resampling based inference that can be used to compare two groups. A simple univariate two-group permutation test requires that the group labels for the observations are exchangeable under the null hypothesis of equal distributions, but allows relaxation of specific distributional assumptions required by ...
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A primer to Sweave with LyX

October 24, 2009 | Jitao David Zhang

This is a step-by-step guide to 'Sweave' a document in R with Lyx on Ubuntu (9.04).System: Ubuntu 9.04, LyX 1.6.2, R 2.11.0 (Development version, r50178)Install LyX with Synaptic if it is not installed yet. (Current version 1.6.2)Start LyX, go to menu ... [Read more...]

Data Mining and R

October 24, 2009 | Jeromy Anglim

This post lists a few data mining resources in R. I also provide a few observations on the distinction between data mining, data analysis, and statistics as it pertains to the analysis work that I do in psychology.Online ResourcesThe classic book The E...
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RSPerl : Using R from within Perl

October 23, 2009 | Stewart MacArthur

Some things I write in perl some in R, sometime I use perl to write R and run R. One thing that I find very useful is the functionality of RSPerl which enables you to call R functions from within perl and on perl variables. It can also call perl ... [Read more...]

ISO week

October 22, 2009 | Forester

I am working with a model that produces estimates of snow water equivalent through time. Because I deal with large spatial extents, I decided to have the model produce weekly averages. The problem with this is knowing which file to access for a given d... [Read more...]

Leap years

October 22, 2009 | Forester

A quick function that when provided a numeric vector of years returns a boolean vector where TRUE == Leap year.is.leapyear=function(year){ #http://en.wikipedia.org/wiki/Leap_year return(((year %% 4 == 0) & (year %% 100 != 0)) | (year %% 400 == 0))} [Read more...]
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