The R Bloggers website, maintained by Tal Galili, aggregates blogs (including mine) from many people of the R community. Tal and I have been wondering about how to tight R Bloggers with the gallery, supporting each other's website. To that extent...
Monthly Archives: October 2011
Risk, Return and Analyst Ratings
Today I want to discuss a connection between Risk, Return and Analyst Ratings. Let’s start with defining our universe of stocks : 30 stocks from Dow Jones Industrial Average (^DJI) index. For each stock I will compute the number of Upgrades and Downgrades, Risk, and Return in 2010:2011. I will run a linear regression and 
Because it’s Friday: Reviews of Random Digits
If you dig around enough on Amazon.com, you can find some pretty odd products (like the Badonkadonk tank now sadly unavailable). Attached to these products you can often find a new form of comedy: the funny Amazon review. The products that attract such attention can be hard to fathom: this gallon of milk has more than 1,000 reviews. (Sample:...
All combinations for levelplot
In a previous post I explained how to create all possible combinations of the levels of two factors using expand.grid(). Another use for this function is to create a regular grid for two variables to create a levelplot or a … Continue reading →
In case you missed it: September Roundup
In case you missed them, here are some articles from September of particular interest to R users. The deadline to enter the "R Applications" contest with $20,000 in prizes is October 31. The RHadoop Project, a new collection of open-source R packages from Revolution Analytics, makes it possible to write map-reduce jobs in R to analyze huge data sets...
R Workshop: Reading in Large Data Frames
One question I get a lot about how to read large data frames into R. There are some useful tricks that can save you both time and memory when reading large data frames but I find that many people are not aware of them. Of course, your ability to read...
When Wellington meets the “animation” package
The “animation” package is great for creating .gif files (of course, it also produces video and flash files thanks to Yihui Xie). By using this package, I would like to show you a nice spot in Wellington, NZ. At this … Continue reading →
FFT / Power Spectrum Box-and-Whisker Plot with Gggplot2
I have a bunch of time series whose power spectra (FFT via R's spectrum() function) I've been trying to visualize in an intuitive, aesthetically appealing way. At first, I just used lattice's bwplot, but the spacing of the X-axis here really matters. ...
Visualizing Tables with plot.table
plot.table function in the Systematic Investor Toolbox is a flexible table drawing routine. plot.table has a simple interface and takes following parameters: plot.matrix – matrix with data you want to plot smain – text to draw in (top, left) cell; default value is blank string highlight – Either TRUE/FALSE to indicate if you want to 
Assumptions of the Linear Model
Linear Assumptions from the Analysis Factor – Assumptions of linear regression (and ANOVA) are about the residuals, not the normality or independence of the response variable (Y). If you don’t know what this means be sure to read this brief … Continue reading →
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
