Some scholars suggest that multiply imputing an outcome variable is incorrect. I use intuition and simulation to argue that multiply imputing outcomes can drastically improve estimates, even in the case of non-ignorable missingness. Continue reading &#... [Read more...]
Every year there is at least a couple of occasions when I have to simulate multivariate data that follow a given covariance matrix. For example, let’s say that we want to create an example of the effect of collinearity when … Continue reading → [Read more...]
The only thing that separates the United States from Europe and the notorious PIIGS is the generosity of Asian Central Banks who have been consistently quantitatively easing since 1998 (Join the Reserves). From TimelyPortfolio Without this generos...
I normally work with full numerical data, not categorical data. R, when using read.csv() seems to recognize such categories and marks the column as to have factor levels. This is useful indeed. However, I wanted to make a PCA biplot on this data, so wa... [Read more...]
Update 10/11/2011: There’s a good discussion on RedditUpdate 10/12/2011: Note manipulate package and highlight data.table packageThe R statistical computing platform is a rising star that’s been gaining popularity and attention, but it gets no respect in the hood. It’s telling that a popular guide to R is called ... [Read more...]
Karl Broman writes: Barry Rowlingson gave an interesting talk at UseR 2011, “Why R-help must die!” He suggested the Q-and-A type sites Stack Overflow (on programming) and Cross Validated (on statistics), both part of Stack Exchange. I haven’t used R-help recently but I do occasionally send people there. Just to ... [Read more...]
Yesterday I launched my first question at Stackoverflow and apparently did a lot of things wrong as I managed to get my question closed wihtin hours http://stackoverflow.com/questions/7728462/identify-records-in-data-frame-a-not-contained-in-data-frame-b I had collected 9 different solutions to the problem and made the mistake to put it all within the original ... [Read more...]
NOTE : This tutorial has been superseded by the exhaustive tutorials Here Lists Collection of Objects of same or mixed type.List may also contain vector or other lists. Create a list using the funtion list(). The following example shows operations that can be performed on a list. __ alphabets=list(a=”... [Read more...]
How many R related books have been published so far? Who is the most popular publisher? How many other manuals, tutorials and books have been published online? Let's find out. A few years ago I used the publication list on r-project.org as an argument ...
This code creates a decision tree model in R using party::ctree() and prepares the model for export it from R to Base SAS, so SAS can score new records. SAS Enterprise Miner and PMML are not required, and Base SAS … Continue reading → [Read more...]
As Le Monde weekend has yet again changed its format (with so much more advertisements for luxurious items that I sometimes wonder whether or not this is the weekend edition of Le Monde!], it took me a while to locate the mathematical puzzle. The good news is there now is ... [Read more...]
(Contributing blogger Joe Rickert has put together a fantastic list of data sources suitable for use with R. If you're looking for data to use in the Applications of R Contest -- entries close October 31 -- this is a great resource for you -- Ed.) Hardly a day goes by ... [Read more...]
This is simple example code to display side-by-side lattice plots or ggplot2 plots, using the mtcars dataset that comes with any R installation. We will display a scatterplot of miles per US gallon (mpg) on car weight (wt) next to … Continue reading → [Read more...]
Following last post about partnership with R Bloggers, Tal and I have added a small widget to the gallery main page to present links to recent posts on R Bloggers
It uses the wordpress api to grab information about the rss feed generated by R Bl... [Read more...]
The Occupy Wall Street movement chants "We are the 99 percent, you are the 1 percent." It's a catchy refrain, and there are many excellent reasons to put the focus on Wall Street in the struggle for economic and political justice in the US. But even singling out one percent of the ... [Read more...]
TheBestColleges.org has just published their list of the "Top 50 Statistics Blogs of 2011", and I'm pleased say that not only did our own Revolutions blog make the list, but it's in fine company with some truly excellent blogs. Several of my personal favourites made the list, including: Guardian columnist Ben ... [Read more...]
I tend not to upgrade R very often—running from 6 months to 1 year behind in version numbers—because I had to reinstall all packages: a real pain. A quick search shows that people have managed to come up with good … Continue reading → [Read more...]