The New York Times introduced R to the world with a feature article in 2009, and has been using R for many years to support its pioneering presentation data analysis and visualization, under the direction of graphics editor Amanda Cox. Last week, the New York R User Group's featured speaker was ... [Read more...]

Working on some new ideas on how map unit data can be summarized on small screens-- particularly for our mobile version of SoilWeb. The distance from the nearest map unit polygon boundary is now printed above mini soil profile sketches. This gives the ... [Read more...]

Hi,these days I'm working with soil textural data and one of the key point of these data is the presentation of the results.The best way is a old-school texture triangle!!!Because I like to do all my stuff in R, instead of opening draw software such as... [Read more...]

In my last two posts I talked about Ordinary Least Squares, then extended this discussion to the multiple predictor case and briefly talked about some of the problems that may arise. These problems can include omitted variable bias, heteroskedasticity, non-normality, and multicollinearity. Most of these problems are relatively minor in ... [Read more...]

For coding in R i wanted something simple. Like using it in Eclipse. StatET was the perfect solution for me. It mqkes you able to call a console of R into Eclipse and do everything from Eclipse. So let’s install it. Since I had some troubles inst... [Read more...]

Exercise 4 is all about using Newton's Method to implement logistic regression on a classification problem. For all this to make sense i suggest having a look at Andrew Ng machine learning lectures on openclassroom. We start with a dataset representing 40 students who were admitted to college and 40 students who were ... [Read more...]

Here, by Charles J. Geyer. [Read more...]

I am a regular reader of the FlowingData blog by Nathan Yau. It is an excellent reference for anyone interested in statistical visualization of data. One of his posts that caught my attention was a visualization of the growth of Walmart in the US. Given my research interests in retail, ... [Read more...]

Since I just didn’t get enough this morning, I spent some more time fooling around with estimating pi. Since I was basically counting the number of random x,y pairs inside a quarter circle and computing a sample average for more … Continue reading → [Read more...]

[Read more...]

A quick reminder that Revolution Analytics' CTO David Champagne will be hosting a live webinar tomorrow (March 16) on Integrating R into 3rd Party and Web Applications Using RevoDeployR. Designed for application developers, this webinar will cover publishing R scripts to the RevoDeployR server, and integrating their results into Web applications, ... [Read more...]

The Orange County R User Group was formed to bring local R users together in a friendly, business-oriented environment. This is the fifth R user group in California. Founder Ray DiGiacomo, Jr. says, "I feel this group is necessary because the current Los Angeles and San Diego R User Groups ... [Read more...]

[Read more...]

No need to do politics. Just take a statistical course. And I do not talk about misinterpretation of statistics, but I talk about the mathematical foundations of statistical tests. Consider the following parametric test, with a one-dimensional para... [Read more...]

I just heard that my supervisor's book Chemometrics with R was released, and I immediately requested our library to get a copy. Ron introduced me to R at a time that most at our department were still using Matlab. In fact, I had be maintaining Matlab s... [Read more...]

It is officially no longer pi day, but I didn’t see this Drew Conway post about estimating pi until just a few minutes ago. Because Google Reader doesn’t show github embeds, I also got to try it without seeing Drew’s … Continue reading → [Read more...]

(This is a guest post by Damian from Skill Analytics and ETF Prophet) Let me start by saying that I’m not an expert in backtesting in Excel – there are a load of very smart bloggers out there that have, as I would say, “mad skillz” at working with Excel ... [Read more...]

[Read more...]

I received an email today with the following comment: I’m using ARIMA with Intervention detection and was planning to use your package to identify my initial ARIMA model for later iteration, however I found that sometimes the auto.arima function returns a model where AR/MA coefficients are not ... [Read more...]

As you may know, today is Pi Day, when all good nerds take a moment to thank the geeks of antiquity for their painstaking work in estimating this marvelous mathematical constant. It is also a great opportunity to thank contemporary geeks for the wonders of modern computing, which allow us ... [Read more...]