IntroductionA triangle test is a test beloved by sensory scientists for its simplicity and general use in detecting presence of product differences. The principle is simple. Test subjects get served three samples. One of these contains A, two of these ... [Read more...]

Today, I want to highlight the Financial Turbulence Index idea introduced by Mark Kritzman and Yuanzhen Li in the Skulls, Financial Turbulence, and Risk Management paper. Timely Portfolio did a great series of posts about Financial Turbulence: Part 1, Part 2, Part 3. As example, I will compute Financial Turbulence for the equal ... [Read more...]

I’ve made the acquaintance of a group of data analysts here in the triangle and have agreed to arrange an outing to the Durham Bulls minor league baseball team. Because it’s for stat nerds and because I was curious, I went looking for some baseball data to analyze. ... [Read more...]

The concept is to make a GUI to provide a static and dynamic linking between data and its network representations. Static access will involve making networks based on data and metadata stored in some table or spreadsheet. Dynamic control will provide interactive access to network construction and annotation properties. Together, ... [Read more...]

We’re going to try, this December, to bring you an “Advent CalendaR,” for each of the 24 days leading up to Christmas. Each day, our hope is to unwrap a useful R package to show you a useful or interesting function inside! Today&#821... [Read more...]

Discussing with some friends the other day, one of them mentioned a supposedly famous quote from Einstein saying that 1 + 1 = 3. Despite my best efforts, Google couldn’t find that particular quote. Anyway, we were trying to understand how could have Einstein come up with that. Our answer was that the proposition “1 + 1 = 3” ... [Read more...]

Finally all the stars have aligned and I can confidently devote some time for back-testing of new trading systems, and Support Vector Machines (SVM) are the new “toy” which is going to keep me busy for a while. SVMs are a well-known tool from the area of supervised Machine Learning, ... [Read more...]

Computer Science PhD student Tim Weninger wrote a 10-page paper for the World Wide Web conference looking at how Reddit users interact on the discussion pages of the social news site. During the process, he saved 463 revisions of the paper in a source-code control system. Then, he wrote a computer ... [Read more...]

Can R be used for real-time applications? Absolutely! The key is in setting up an technology stack that can support real-time interactions with models developed in R ... and a clear understanding of what "real-time" really means, and its implications in the context of Big Data. I explained how this works ... [Read more...]

Last week in Davis R Users’ Group, Lauren Yamane showed us how she created and analyzed a stochastic age-structured population in R. Her examples are below. Her original scripts can be found as *.Rmd files here A note to UC Davis students: This topic and others will be covered by ... [Read more...]

First, an update:  A commentator has asked me to post my code so that it is easier to practice the examples I show here.  It will take me a little bit of time to get all of my code for past posts well-documented and readable, but I have uploa... [Read more...]

Finally, to return to the challenge I laid out in the first of this series on image manipulation in R: can we do anything as cool in R as can be done in Mathematica? Like, for example, this illustration of how to search images of the surface of Mars... [Read more...]

Here’s a code snippet I thought I’d share. Very often I find myself checking the output of a function f(a,b) for a lot of different values of a and b, which I then need to plot somehow. An example: here’s a function that computes the ... [Read more...]

Different from RPy2, PypeR provides another simple way to access R from Python through pipes (http://www.jstatsoft.org/v35/c02/paper). This handy feature enables data analysts to do the data munging with python and the statistical analysis with R by passing objects interactively between two computing systems. Below ... [Read more...]

This is a brief example using the maps in R and to highlight a source of data.  This is real-time data and it comes from the U.S. Geological Society.  This shows the location of earthquakes with magnitude of at least 1.0 in the lower 48 states. library(maps) library(maptools) library(... [Read more...]

This report describes the animaker package for generating descriptions of animation sequences. An animation sequence is composed by combining atomic animations in series to create sequence animations or in parallel to create track animations. Functions are provided for manipulating animation … Continue reading → [Read more...]

Yihui Xie is the creator of several popular R packages, including knitr, animation and cranvas. In an interview with The Setup, he shares some of the software and hardware he uses in his data-to-day work, including (of course) R: For programming and data analysis, I primarily use R since I'm ... [Read more...]

Several of you will probably have tried out the new Shiny package brought to the table by the RStudio guys This is just what I have been looking for and to my mind could provide a quantum leap in the use of R. There have been other packages addressing the ... [Read more...]

DefaultBy default, lattice sorts the observations by the axis values, starting at the bottom left.For example,library(lattice)colors = c("#1B9E77", "#D95F02", "#7570B3")dotplot(rownames(mtcars) ~ mpg, data = mtcars, col = colors[1], pch = 1)produc... [Read more...]

In a recent post by Revolution Analytics (link & link) in which Revolution was benchmarking their closed source generalized linear model approach with SAS, Hadoop and open source R, they seemed to be pointing out that there is no 'easy' R open source solution which exists for building a poisson regression ... [Read more...]