In Crazy RUT, I started to explore why the moving average strategy has failed for the last 2 decades on the Russell 2000. I still do not have an answer, but I thought looking at skewness and kurtosis might help explain some of the challenge of be...

Seeing as more people were interested in how I created my slides for the R conference than what was actually on them, I posted my source and commands to github. I used knitr with Rmarkdown source to convert to markdown that went into pandoc to create beamer slide. Enjoy! https://gist.github.com/2955183

A quick heads-up that I'll be hosting a live webinar this Wednesday (June 20) with my colleage Sue Ranney on the new Revolution R Enterprise 6. If you've never taken a look at Revolution R Enterprise and want to know it's different from open-source R, or just want to learn about the new features, then please join us on...

Introduction I recently posted about using the Wikileaks cable corpus to find word use patterns, both over time, and in secret cables vs unclassified cables. I received a lot of good suggestions for further topics to pursue with the corpus, and probably the most interesting was the idea to do sentiment analysis over time on a variety of...

Arguably, knitr (CRAN link) is the most outstanding R package of this year and its creator, Yihui Xie is the star of the useR! conference 2012. This is because the ease of use comparing to Sweave for making reproducible report. Integration of knitR and R Studio has made reproducible research much more convenience, intuitive and easier to

A colleague asked for help with randomly choosing a kid within a family. This is for a trial in which families are recruited at well-child visits, but in each family only one of the children having a well-child visit that day can be in the study. The idea is that after recruiting the family, the research assistant...

This is a follow up to my previous post. There is a quicker way to compute the function I created (basic cumulative sum) in R.Instead of:function f(x) { sum = 0; for (i in seq(1,x)) sum = sum + i return(su...