The following R code models a censored dependent variable (in this case academic aptitude) using a traditional least squares, tobit, and Bayesian approaches. As depicted below, the OLS estimates (blue) for censored data are inconsistent and will ...

Brown-bag release time for littler. One of the minor cleanups in the 0.1.4 release from Thursday actually introduced a nasty little bug as you can't call Rf_KillAllDevices() when you do not have any graphics device. Doh. So with apologies for the l...

The School of Mathematics & Statistics at Newcastle University (UK), are again running some R courses. In January, 2012, we will run: January 16th: Introduction to R; January 17th: Programming with R; January 18th & 19th: Advanced graphics with R. The courses aren’t aimed at teaching statistics, rather they aim to go through the fundemental

posterior = (likelihood x prior) / integrated likelihoodThe combination of a prior distribution and a likelihood function is utilized to produce a posterior distribution. Incorporating information from both the prior distribution and the likelihood function leads to a reduction in variance and an improved estimator. As n→...

If you also favor to use the function, be aware of the returned value. For example:> ifelse(1>0, 3, 4) 3> ifelse(1>0, c(2, 3), c(4, 5)) # only the first element returned. 2 > ifelse(c(1:10)>5, 'on', 'off') "off" "off...

Revolution Analytics' Joe Rickert has a new post on inside-R.org, demonstrating how you can use R and the RevoScaleR package to extract time series data from time-stamped logs (in this case, the "US Domestic Flights From 1990 to 2009" dataset on Infochimps): Analyzing time series data of all sorts is a fundamental business analytics task to which the R...

Some pictures to explore the reality of the theory that stocks with higher beta should have higher expected returns. Figure 2 of “The effect of beta equal 1″ shows the return-beta relationship as downward sloping. That’s a sample of size 1. In this post we add six more datapoints. Data The exact same betas of … Continue reading...

After working more seriously with simulations I noticed some updates were necessary to my previous setup. Most notably are the following three: It is very handy to explicitly call the different scenarios instead of using nested loops Storing intermediate results in single files obliviates the need to rerun an almost finished but crashed analysis and

Wes McKinney is a prominent figure in the scientific Python community, and has made tremendous contributions to several core statistical computing libraries in that language. This month, Wes will be speaking specifically about two packages he has crea...

Lloyd's is the world's leading specialist insurance market, and is often the first to insure new, unusual or complex risks. So it's no surprise that Lloyd's is one of the many companies that use R and its advanced capabilities for data analysis to help manage its insurance risks. At the useR! conference last month, Lloyd's analysts Markus Gesmann, Viren...

Prompted by a rush of visitors from Andrew Gelman's blog, I went back and updated the details of my post from 2009 on reading data from Google Spreadsheets into R. Since then, Google had switched to using a secure (https) connection for Google Docs, which required some tweaks to the code. If you haven't seen it before, it's a...

Matthias Klose, the tireless force behind the Debian / Ubuntu gcc, python, and what have you packages, sent me a minimal patch to let littler build when the ld linker uses the --as-needed option (as Ubuntu builds now do): all it took was a little reor...

New version of our 'aqp' package for quantitative soils investigations, available on CRAN (version 0.99-5) and R-Forge (0.99-8). Some of the major changes are listed below: -------------------------- aqp 0.99-8 (2011-09-14) -------------------------- ...