if you've ever gotten stuck in traffic and started wondering what data might be available to better design the network of roads and rail, rev your engines for the national household travel survey (nhts).  dating back to the same decade as eisenhow... [Read more...]

Spring is at hand and it is a time of renewal, March Madness and to settle scores in the NHL.  There are many scores to be settled: Flyers vs. Penguins, Blackhawks vs. Red Wings, Leafs vs. Habs and pretty much everyone else vs. the Bruins.  L... [Read more...]

One of my students complained that his slice sampler of a Poisson distribution was not working when following the instructions in Monte Carlo Statistical Methods (Exercise 8.5). This puzzled me during my early morning run and I checked on my way back, even before attacking the fresh baguette I had brought ... [Read more...]

[This article was first published on theBioBucket*, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share your [Read more...]

I am applying for Google Summer of Code 2014 again with “Biodiversity Data Visualizations using R” proposal. We are proposing to take package bdvis to next level by adding more functions and making it available through CRAN. I am posting this idea to get feedback and suggestions from Biodiversity Informatics community. [... [Read more...]

Correlation does not imply causation, sure but, as Edward Tufte writes, “it sure is a hint.” The Pearson product-moment correlation coefficient is perhaps one of the most common ways of looking for such hints and this post describes the Bayesian First Aid alternative to the classical Pearson correlation test. Except ... [Read more...]

CARE International is a humanitarian organization that is leading the charge to fight poverty around the world, with a focus on empowering women and girls. On March 28 in Atlanta, CARE is teaming up with Booz Allen Hamilton, Emory University's Rollins School of Public Health and Revolution Analytics to bring data ... [Read more...]

Like every start-up in the IT and data science sector, we often find ourselves spending more time on Stack Overflow than on our own site. For those of you who are not familiar with it, Stack Overflow is like a Q&A forum on steroids. It features questions and answers ... [Read more...]

The leave-one-out cross-validation statistic is given by     where , are the observations, and is the predicted value obtained when the model is estimated with the th case deleted. This is also sometimes known as the PRESS (Prediction Residual Sum of Squares) statistic. It turns out that for linear models, we do ... [Read more...]

[This article was first published on Rmetrics blogs, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share your [Read more...]

[This article was first published on Rmetrics blogs, and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share your [Read more...]

The rOpenSci projects aims to provide programmatic access to scientific data repositories on the web. A vast majority of the packages in our current suite retrieve some form of biodiversity or taxonomic data. Since several of these datasets have been georeferenced, it provides numerous opportunities for visualizing species distributions, building ... [Read more...]

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The above is the running head of the arXived paper with full title “Implications of  uniformly distributed, empirically informed priors for phylogeographical model selection: A reply to Hickerson et al.” by Oaks, Linkem and Sukuraman. That I (again) read in the plane to Montréal (third one in this series!, ... [Read more...]

Numerous psychological studies have demonstrated that people often have an inflated perception of their personal qualities. From work performance to driving skills, people report being above average in relation to others when it comes to many arenas. This extends to how people perceive their own physical attractiveness and intelligence levels. ... [Read more...]

It's been a while since I analysed something with R. I decided to pick into Dota 2 statistics. This game is the real eSport now with players fighting for respectable prise pools. And the main Dota 2 event is The International where best teams compete each other in astonishing battles. So I ... [Read more...]

More efficiency and an additional function in the new version on CRAN. Variance estimation The major functionality in the package is variance estimation: Ledoit-Wolf shrinkage via var.shrink.eqcor statistical factor model (principal components) via factor.model.stat There have been a number of previous blog posts on both factor ... [Read more...]

In this third PK posting I move to chapter 10, study problem 4 of Rowland and Tozer (Clinical pharmacokinetics and pharmacodynamics, 4th edition). In this problem one subject gets a 24 hours continuous dose. In many respects the Jags calculation is not very different from before, but the relation between parameters in the ... [Read more...]

Introduction Box models are popular in some branches of oceanography and other geophysical disciplines, partly because they are simple to construct and to solve. This posting shows how to solve a box model in R, using the lsoda() function in the deSolve package. The basic ideas can be explained in ... [Read more...]

I’ve re-written the previous post a bit and now it is posted in the Rcpp gallery. I’ve had some really good comments, so I’ll probably have to post an updated version. Keep the comments coming! ∞ [Read more...]