The R Graph Gallery has been a popular website for many years now. The number of graphics keeps growing as people send me their code. When browsing the website with a mobile device the experience was frustrating, as too much … Continue reading →

Use R to specify factors, recode variables and begin by-group analyses. Video Files This file contains data on pain score after laparoscopic vs. open hernia repair. Age, gender and primary/recurrent hernia also included. The ultimate aim here is to work out which of these factors are associated with more pain after this operation. lap_hernia Script

How has the distribution of correlations changed over the last several years? Previously Posts about correlation boxplots explained Data Daily returns of 443 large cap US stocks from 2004 through 2012 were used. The sample correlations — almost 98,000 of them — during each year were created. If we were actually using the correlations, then … Continue reading...

I’m working on a one-hour ggplot2 lecture for the San Diego R users group, which I will post here when I’m done. I think there are many great intro to R data visualization resources out there so I’ll only share working examples on my blog. A retail chain client employs a few hundred field agents who perform

JW Emerson, WA Green, B Schloerke, J Crowley, D Cook, H Hofmann, H Wickham (2013) The Generalized Pairs Plot. Journal of Computational and Graphical Statistics 22(1). Here's a free preprint version. Until this new paper and implementation by Emerson et al., there were no widely available pairs plots that accommodated both numerical and categorical fields.

Benford’s law is nowadays extremely popular (see e.g. http://en.wikipedia.org/…). It is usually claimed that, for a given set data set, changing units does not affect the distribution of the first digit. Thus, it should be related to scale invariant distributions. Heuristically, scale (or unit) invariance means that the density of the measure (or probability function) should be proportional to...

If you're laying down a friendly bet on the March Madness games or just tweaking your fantasy roster, this NCAA Data Visualizer by Rodrigo Zamith will be a boon. Just choose two teams to compare head-to-head, choose an attribute to compare them on. You can look at more than a dozen invividual player attributes (e.g. points scored, assists, 3-point...

I learned about Lord Rayleigh’s discovery of argon in my 2nd-year analytical chemistry class while reading “Quantitative Chemical Analysis” by Daniel Harris. (William Ramsay was also responsible for this discovery.) This is one of my favourite stories in chemistry; it illustrates how diligence in measurement can lead to an elegant and surprising discovery. I find