During data analysis, it is often super useful to turn continuous variables into categorical ones. In Stata you would do something like this:gen catvar=0replace catvar=1 if contvar>0 & contvar<=3replace catvar=2 if contvar>3 & co...
Monthly Archives: September 2012
Data Frames and Transactions
Transactions are a very useful tool when dealing with data mining. It provides a way to mine itemsets or rules on datasets. In R the data must be in transactions form. If the data is only available in a data.frame then to create (or coerce) the data frame to transaction the researcher may use the
Coursera’s free online R course starts today
Coursera offers a number of on-line courses, all available for free and taught by experts in their fields. Today, the course Computing for Data Analysis begins. Taught by Johns Hopkins Biostatistics professor (and co-author of the Simply Statistics blog) Roger Peng, the course will teach you how to program in R and use the language for data analysis. Here's...
An R Users’ Group in Davis
I’m excited to share that we’ve started a new R users’ group at UC Davis! Right now our main purpose is to run weekly 2-hour work/hack sessions where R users can get together to work through problems together. More info here
Example 10.3: Enhanced scatterplot with marginal histograms
Back in example 8.41 we showed how to make a graphic combining a scatterplot with histograms of each variable. A commenter suggested we change the R graphic to allow post-hoc plotting of, for example, lowess lines. In addition, there are further refinements to be made.
In this R-only entry, we'll make the figure...
Use GBIF and googleVis to Make Maps with Species Occurrence Data
This is a short follow up on THIS posting.. I will briefly show how to use the dismo- and the googeVis package to plot species occurrences on an interactive Google map, like the one below (HERE is the R-script)
Computing kook density in R
Do you ever see strange lights in the sky? Do you wonder what really goes on in Area 51? Would you like to use your R hacking skills to get to the bottom of the whole UFO conspiracy? Of course, you would! UFO data from infochimps is the focus of a dat...
qgraph version 1.1.0 and how to simply make a GUI using ‘rpanel’
Last week I have updated the ‘qgraph‘ package to version 1.1.0, available on CRAN now. Besides some internal changes (especially the self-loops have been substantially improved) the most important change is the addition of a GUI interface, which can be … Continue reading →
Simple visually-weighted regression plots
There has recently been a lot of discussion of so-called “visually-weighted regression” plots. Folk hero Hadley Wickham suggests that such plots would be easy to implement with ggplot2, and so I have attempted to prove him right. The approa...
Volatility forecast evaluation in R
In portfolio management, risk management and derivative pricing, volatility plays an important role. So important in fact that you can find more volatility models than you can handle (Wikipedia link). What follows is to check how well each model performs, … Continue reading →
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
