RealClimate.org used the R language and data from the National Snow and Ice Data Center to create this chart showing the extent of Arctic sea-ice in each year since satellite observations began in 1978, and the current extent of ice coverage (in red). Even though there are several weeks of ... [Read more...]

About a year ago I wrote a post about producing scatterplot matrices in R. These are handy for quickly getting a sense of the correlations that exist in your data. Recently someone asked me to pull out some relevant statistics (correlation coefficient ... [Read more...]

A post over on Dang, another error (show me yours and I’ll show you mine) has a method of working with R which uses an IDE called Eclipse in conjunction with a plugin called StatET. Eclipse is one of a number of IDEs that I’m aware of (Tinn-R ... [Read more...]

This week I’m in Cyprus attending the COMPSTAT2012 conference. There’s been the usual interesting collection of talks, and interactions with other researchers. But I was struck by two side comments in talks this morning that I’d like to mention. Stephen Pollock: Don’t imagine your model is ... [Read more...]

[Read more...]

[Read more...]

Updates from RStudio support: (1) “Thanks for reporting and I was able to reproduce this as well. I’ve filed a bug and we’ll take a look.” (2) Taking a further look, this is actually a bug in the Markdown package and we’ve asked the maintainer (Jeffrey Horner) to look ... [Read more...]

Two significant R community milestones were achieved over the weekend. Firstly, the number of community-contributed R packages on CRAN is now above 4000. (As of this writing, it's 4004.) Figure 10 of The Popularity of Data Analysis Software charts the exponential growth of R packages: at the end of last year the figure ... [Read more...]

[Read more...]

I wrote before about heatmap tables as a better way of producing frequency or other tables, with a solution which works nicely in latex. It is possible to do them much more easily in ggplot2, like this library(Hmisc) library(ggplot2) library(reshape) data(HairEyeColor) P=t(HairEyeColor[,,2]) Pm=melt(... [Read more...]

It’s difficult to write a book on an entire programming language and keep it manageable and concise, but The Art of R Programming does it as well as any text I’ve seen. Matloff covers, in detail and among other things, R data structures, programming idioms, performance enhancements, interfaces ... [Read more...]

How much does garch shorten long tails? Previously Pertinent blog posts include: “A practical introduction to garch modeling” “The distribution of financial returns made simple” “Predictability of kurtosis and skewness in S&P constituents” Induced tails Part of the reason that the distributions of returns have long tails is because ... [Read more...]

[Read more...]

People have been telling me for a while that the latest version of RStudio, the IDE for R, is a great way to generate reports. I finally got around to trying it out and for once, the hype is justified. Start with this excellent tutorial from Jeremy Anglim. Briefly: the ... [Read more...]

This post join two things that I like: Highcharts and the Time series. So I have a lot of fun making this minipost to show how works an autoregressive process. Well, let's remember the structure of an autoregresive process. $y_t = varphi,y_{t-1}+epsilon_t$, where $epsilon_t$ is ... [Read more...]

As promised in Halo Effects and Multicollinearity (my last post), I will show how to run a confirmatory factor analysis in R to test our bifactor model.  In addition, I will include a dependent variable and fit a structural equation mode... [Read more...]

[Read more...]

As an invasion biologist, the process of spatial spread is at the heart of what I do. When I came across this dataset of Walmart store openings since 1962 I couldn’t help but see it as an invasion front which looks a lot like a biological invasion or (albeit slow) ... [Read more...]

This post is meant for submitting visual analysis for the Harvard Business Review Contest on KaggleI used the subject lines for all the articles and all the years and mapped the articles into one of the following 18 categories  Business Ethics  Business Management  Crisis  Emerging Markets  Financial Performance  Health Care  Information ... [Read more...]

Economic geography of the eastern USA circa 1999, median incomes by zip code Code and data source to follow in a longer post. [Read more...]