My statistics professor once drew a little Markov chain on the board and called it “just a Mickey Mouse model,” because it was too simple to represent anything serious.
[Update: I've made a website for this: http://www.plannedpooling.com/.]This was a birthday present for my spouse. (Don't worry--I also covered a lot of things -- fruit/nuts/cocoa puffs/etc -- in chocolate. But I think both were appreciated!)Sometimes p... [Read more...]
Here's a video on some of the theory behind simple linear regression.There's no R involved with this video, but the video provides some theory behind what it is that R's lm() command estimates.
In a previous post I discussed my frustrations with trying to get Dropbox or Spideroak to perform BOTH encrypted remote backup and AND fast two way file syncing. This is the detail of how I set up for two machines, both Ubuntu 10.10, to perform two way sync where a file ... [Read more...]
Just got back from the 2011 GEOSTAT summer school that recently took place in Canberra, Australia. Thanks to Tom Hengl for the invitation to co-teach the course, to the great folks at ANU who made it possible, and to all of the students who participat... [Read more...]
I adapted a scheme for a permutation test from the PAST Software (Hammer & Harper, http://folk.uio.no/ohammer/past/diversity.html) that tests difference between diversity-indices of two samples with abundance data... Read more »
Rook is a web server interface and software package for R. It is very much like Ruby’s Rack. In fact it is so much like Ruby’s Rack that I decided to use the same name and basic class hierarchy. You could say I “borrowed heavliy” from Ruby’s ... [Read more...]
This post describes some preliminary results from a compatibility study of the SAS sas7bdat file format. The most current results stored in a github repository here: sas7bdat The ultimate goal is a native solution to the incompatibility between open-source statistical software (e.g. R) and sas7bdat database ... [Read more...]
The first week of April I attended an excellent workshop on biplots held by Michael Greenacre and Oleg Nenadić at the Gesis Institute in Cologne, Germany. Throughout his presentations, Michael used animations to visualize the concepts he was explaining. He also included animations in some of his papers. This inspired ... [Read more...]
Lately I had to figure out how to do a repeated measures (or mixed effects) analysis on multivariate (species) data. Here I share code for a computation in R with the adonis function of the vegan package. Credit goes to Gavin Simpson providing most of ...
How well do asset weight constraints constrain risk? The setup In “Unproxying weight constraints” I claimed that many constraints on asset weights are really a proxy for constraining risk. That is not a problem if weights are a good proxy for risk. So the question is: how good of a ... [Read more...]
Thanks so much for the comment on my last post Historical Bond Price and Total Returns from 10y Yield Series “I know this might sound antithetical to a bond guy, but won't the monthly series get you close enough? “ which proved me wrong and allow...
Update (5/18/2011): Looks like Freakonomics approves as well. Let the record show that I approved first :)I approve: "I use the open-source program R to create the patterns."But, I'm not sure I approve of calling these distributions "evil."In case you...
Producing tables in LaTeX might be a difficult task as we can not just copy and paste a table in the editor; we have to write all the numbers and other codes. But with the help of xtable package of R it is possible to produce all the necessary codes ... [Read more...]
In an earlier post [Speeding tickets for R and Stata] I had reported on how R compared with Stata for executing algorithms involving maximum likelihood estimation. This post offers the following updates on the last post: Stata is in fact even faster than previously reported. The 64-bit version of the ... [Read more...]
(Guest post on R-bloggers by Charlie Sharpsteen) Cameron and I are pleased to announce version 0.6.0 of the tikzDevice package which should be available shortly at your local [Read more...]
I got an interesting message from Chris Atherton the other day who has offered to do a workshop at the Technical Communications UK conference on statistics and data visualisation. The problem is that for some tech writers, their understandin... [Read more...]