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Last week, I left you off at logistic regression. This week, I'll be pushing the limits of regression analysis a bit more with a smoothing technique called LOESS regression. There are a number of smoothing methods that can be used, such as Smoothing ... [Read more...]

In this post, I go over the basics of running an ANOVA using R. The dataset I’ll be examining comes from this website, and I’ve discussed it previously (starting here and then here). I’ve not seen many examples where someone runs through the … Continue reading → [Read more...]

Consider a random pair of binary responses, i.e. with taking values 1 or 2. Assume that probability can be function of some covariates . The Gaussian vector latent structure A standard model is based a latent Gaussian structure, i.e. there exi... [Read more...]

Elastic Compute Cloud (EC2) is a service provided a Amazon Web Services that allows users to leverage computing power without the need to build and maintain servers, or spend money on special hardware. The idea is simple, the user “boots” up one or more machines and then accesses those machines ... [Read more...]

The Oxford English Dictionary includes more than 600,000 words, yet most of us get by in our day-to-day lives with a vocabulary of just a few thousand. In a similar vein, the R language includes thousands of functions: when you start up R 2.13, you have 2832 functions at your disposal: __ length(apropos(".", ... [Read more...]

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Bayesian Model Averaging (BMA) allows for any kind of model prior distributions. While the R package BMS has built-in support for several types of commonly used priors, there may be the need for constructing a custom model prior in a particular exerci... [Read more...]

A discussion on StackOverflow today shows an interesting use of special characters inside the cat function. The most common special characters that you may have come across are the tab and newline characters, represented by \t and \n respectively. Try them for yourself. cat("Red\tlorry\nYellow\tlorry\n") cat ... [Read more...]

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Following the post by Arthur Charpentier (Freakonometrics), I wondered what would be the outcome considering my current engagement (veterinary medicine, epidemiology, bovine mastitis). Briefly, Arthur Charpentier’s post looked at clusters of journals publishing the same kind of papers. So I looked at 25 journals (Journal of Dairy Science, Canadian Journal ... [Read more...]

Yet another paper on ABC model choice was posted on arXiv a few days ago, just prior to the ABC in London meeting that ended in the pub above (most conveniently located next to my B&B!). It is written by Olivier Francois and Guillaume Laval and the approach relies ... [Read more...]

I meant to blog about the R/Finance conference during a lull, but I didn’t find too many. Unlike many conferences I’ve been to the structure of R/Finance was simple: one room and one speaker at a time. Relying on each … Continue reading → [Read more...]

Heads-up to anyone attending the sold-out Data Science Summit in Las Vegas this week: I'll be there tomorrow and Thursday for the conference and to discuss R on the panel discussion "Data Science Toolset - Recipes That Win" (more details about the panel discussion below.) I'm looking forward to meeting ... [Read more...]

Retail Commodity Investors – A bleeding indicator?With the recent “flash crash” in commodities it seemed like a good time to delve into the question of how retail investors react to commodity prices and their investment flows into and out of commodities.  Some of the single commodity investment pools (a.k.... [Read more...]

Two types of R users My overwhelming impression from UseR 2010 is that, generally speaking, there are 2 types of regular R users -- those who have heard and are made uncomfortable by the idea of the *apply() functions, and those who really get it. In ... [Read more...]

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After a week's worth of work in the field, I typically have several pages of hand-written field notes that are associated with GPS waypoints-- badly in need of some kind of transcription/organization. I have yet to find a simple approach for bringing t... [Read more...]

Wunderground Example The Wunderground.com website offers several creative interfaces to current and historic weather information. One of the more interesting features is the URL-based interface to personal weather stations. As far as I can tell, the Wu... [Read more...]

The Rmetrics Association is once again holding its annual Workshop and Summer School on Computational Finance and Financial Engineering at Meielisalp (on Lake Thune in Switzerland) from June 26-30. Now in its fifth year, the workshop consists of Summer School-like tutorial sessions and a user/developer meeting: Both focus on ... [Read more...]