The latest version of futile was released to CRAN yesterday. This release broke out the various functions into self-contained sub-packages …Continue reading »

The relatively (to this decade) cool 2008 global temperatures spurred talks of a warming pause, or even global cooling. The claim usually comes from people who cherry picked either data sets and(!)/or start and end points of the global temperature trends to back up their allegation. The blogosphere already has a lot on this: Skeptical

Since my first representation of the rank statistic as paired was incorrect, here is the histogram produced by the simulation perm=sample(1:20) saple=sum(abs(sort(perm)-sort(perm))) when . It is obviously much closer to zero than previously. An interesting change is that the regression of the log-mean on produces > lm(log(memean)~log(enn)) Call: lm(formula = log(memean) ~ log(enn)) Coefficients: (Intercept)

How many times have you been disappointed by nice trading system, because neither trading cost or slippage or bid/ask spread were included into back-test results? Did you find difficult to back-test a portfolio in R or many portfolios with different stocks? Blotter package is supposed to solve these problems. In really – it is complicated. I

I've been using GenABEL for some time now for GWAS analysis using related individuals. It has an excellent set of functions for estimating a kinship matrix from a dense marker panel and then using this in a linear mixed effects model to allow for relat...

While there's been an informal coterie of R users in the Chicago area for some time (notably the fine folks behind the successful R/Finance conferences) there hasn't been a formal R User Group. Until now, that is. JD Long has taken the plunge and announced the new Chicago R User Group on meetup.com. If you're in the Chicagoland area,...

Here is my personal list of rules of thumb for people who want to meet some R gurus (quickly) in the R help mailing list ([email protected]): If you want to meet Dr Bill Venables, just say something about Type III Sum of Squares (better if you also mention the “unbeatable” SAS); If you want to

MATLAB has a nice program called pplane that draws phase planes of differential equations models. pplane on MATLAB is an elaborate program with an interactive GUI where you can just type the model to draw the phase planes. The rest you fidget by clicking (to grab the initial conditions) and it draws the dynamics automatically.

R Twitterer ech0chrome reports that (s)he has successfully installed R on an iPhone. I haven't tried it myself, since it requires jailbreaking the iPhone, but full instructions have been posted to the R Wiki. It seems that once you have Debian installed on the iPhone, it's simply a matter of installing the required Debian packages. Seems like a neat...

Following a comment from efrique pointing out that this statistic is called Spearman footrule, I want to clarify the notation in namely (a) that the ranks of and are considered for the whole sample, i.e. instead of being computed separately for the ‘s and the ‘s, and then (b) that the ranks are reordered for

We spent last week in the LA area and had a generally good time out west. I was able to sneak in two talks and a group discussion, thanks to the help by Jan de Leeuw (and everybody at UCLA's Stats department) as well as by Szilard Pafka representing ...

We spent last week in the LA area and had a generally good time out west. I was able to sneak in two talks and a group discussion, thanks to the help by Jan de Leeuw (and everybody at UCLA's Stats department) as well as by Szilard Pafka representing th...

We spent last week in the LA area and had a generally good time out west. I was able to sneak in two talks and a group discussion, thanks to the help by Jan de Leeuw (and everybody at UCLA's Stats department) as well as by Szilard Pafka representing ...

In the puzzle found in Le Monde of this weekend, the mathematical object behind the silly story is defined as a pseudo-Spearman rank correlation test statistic, where the difference between the ranks of the paired random variables and is in absolute value instead of being squared as in the Spearman rank test statistic. I don’t

The new help system that was introduced in R 2.10.0 and documented in an article of the R journal is very promising. One thing that is planned for future versions of R (maybe 2.12.0) is some way to include images into Rd documents using the fig option of the Sexpr macro Another way is to use data...

Yesterday, Drew Conway posted an analysis of the survival time to events on Chatroulette. If you're familiar with Chatroulette, you'll know what kind of events you can expect to occur when using it. (If you're not, here's a hint: don't try it now if you're at work.) Sadly, it was all an April Fool's Day joke. But Drew takes...

Tomislav Hengl of the University of Amsterdam has published new book, A Practical Guide to Geostatistical Mapping. It's jam-packed with 291 pages on mapping and analyzing spatial data using free software including R, SAGA, GRASS, ILWIS and Google Earth, and freely-available map data. The book itself is also available for free, as an Open Access Publication. You can order...

Did you really think that a team of researchers spent their weekends counting the number of shirtless adolescent men and exposed penises they could find on charoulette.com? Perhaps you should not answer that, as it may be a better measure of your opinion of sociologist than gullibility. It is true, sociologist do say the

I’ve found this standard normal random number generator in a number of places, one of which being from one of Paul Wilmott’s books. The idea is that we can use the Central Limit Theorem (CLT) to easily generate values distributed according to a standard normal distribution by using the sum of 12 uniform random

Rumor has it that Joe Adler, author of the O’Reilly Book R in a Nutshell, has joined Linked In as a data scientist. But that does not keep him from still pumping out some interesting content over at OReilly.com. His latest article is about lookup performance in R. He does a great job giving code

This quarter I am TAing UCLA’s Statistics 102C. Introduction to Monte Carlo Methods for Professor Qing Zhou. This course did not exist when I was an undergraduate, and I think it is pretty rare to teach Monte Carlo (minus the bootstrap if you count that) or MCMC to undergrads. I am excited about this class because to me, MCMC...

The previously mentioned Regression Modeling Strategies short course taught by Frank Harrell is nearly over. Here are the handouts (PDF) from the course. Keep an eye out here, I'll be writing a few more posts in the near future on topics Frank covered...

In this post I will provide R code that implement’s the combination of repeated running quantile with the LOESS smoother to create a type of “quantile LOESS” (e.g: “Local Quantile Regression”). This method is useful when the need arise to fit robust and resistant (Need to be verified) a smoothed line for a quantile (an example for such a...

Noted statistician Andrew Gelman has teamed up with occultist George Romero to address the most serious public-health threat of out time: Zombies. They've published a paper in the journal Biomastika, "How many zombies do you know?" to propose the use of indirect survey methods to measure outbreaks of the undead: Abstract: The zombie menace has so far been studied...