As announced by David Smith over at Revolution Analytics, a ggplot2 Case Study Competition is on... Rather than blogging for the last few days, I cobbled together an entry. It is not a particularly mind bending use of ...
Monthly Archives: September 2010
Eigenimages: The AT&T Cambridge Faces Database
I picked up the AT&T Laboratories Cambridge database of faces for a clustering application. The database consists of images of 40 distinct subjects, each in 10 different facial positions and expressions. Typically, the goal of clustering in these data is to recover the ‘true’ partition, or that which isolates images of distinct subjects. Each image
Revolution R Enterprise 4.0 free download for academics
The Windows version of our latest enterprise distribution of R, Revolution R Enterprise 4.0, is now being delivered to subscribers and is also available for free download for members of the academic community. Revolution R Enterprise 4.0 is a major update, and includes many new and improved features: Based on R 2.11.1, the current release of the R. See...
Barchart or Dotchart?
Which of the following two charts (both created with R) to you prefer? This dotchart: Or this bar chart? Andrew Gelman (who, incidentally, is speaking at the October NYC UseR meeting) prefers the dotchart prefers a line plot (update: see Gelman's comment, below), but personally I think the bar chart is more easily interpreted. What do you think? You...
Example 8.4: Including subsetting conditions in output
A number of analyses perform operations on subsets. Making it clear what observations have been excluded or included is helpful to include in the output.SASThe where statement (section A.6.3) is a powerful and useful tool for subsetting on the fly. (...
Embed R Code with Syntax Highlighting on your Blog
If you use blogger or even wordpress you've probably found that it's complicated to post code snippets with spacing preserved and syntax highlighting (especially for R code). I've discovered a few workarounds that involve hacking the blogger HTML templ...
Writing a Spatial Function: The Location Quotient
Background: In some cases it is necessary to conduct the same analysis multiple times on either the same or different data. In such circumstances it is worth writing a function to simplify the code. In this example the location quotient provides a simple calculation easily written in to a function. The location quotient (LQ) is
Canterbury Earthquakes part II
Since posting last night, there's been several more aftershocks, including several big ones. The total now stands (at 7:00pm) at 304 aftershocks, 70 greater than 4 on the Richter scale, 29 greater than 4.5, and 10 greater than 5. A couple of the fives ...
Canterbury Earthquakes part II
Since posting last night, there's been several more aftershocks, including several big ones. The total now stands (at 7:00pm) at 304 aftershocks, 70 greater than 4 on the Richter scale, 29 greater than 4.5, and 10 greater than 5. A couple of the fives ...
Confidence Bands for Universal Scalability Models
In the recent GDAT class, confidence intervals (CI) for performance data were discussed. Their generalization to confidence bands (CB) for scalability projections using the USL model also came up informally. I showed a prototype plot but it was an ugly hack. Later requests from GDAT attendees to apply CBs to their own data meant I had...
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
