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Earlier this weekend (Dec. 7, 2013), mnlogit was released on CRAN by Wang Zhiyu and Asad Hasan ([email protected]) claiming that mnlogit uses “parallel C++ library to achieve fast computation of Hessian matrices”. Here is a comparison of mnlogit with mlogit by Yves Croissant whose package seems to be the ... [Read more...]

Tim Hortons Density Inspired by this post, I wanted to examine the locations and density of Tim Hortons restaurants in Canada. Using Stats Canada data, each census tract is queried on Foursquare for Tims locations. Setup

options(stringsAsFactors = F)
require(timmysDensity)
require(plyr)
require(maps)
require(ggplot2)
require(geosphere)

Statistics Canada Census Data The actual Statistics Canada data at the dissemination block ... [Read more...]

 Probably the last post before year end and very typical for me is to review this years system performance. A couple of R-packages are since 1 year the backbone of my lab. Just recently I added a package called "Forecast" which is a brilliant im... [Read more...]

Welcome to the second part of series blog posts! In previous part, we discussed on the concept of the logistic regression and its mathematical formulation. Now, we will apply that learning here and try to implement step by step in R. (If you know concept of logistic regression then move ... [Read more...]

Following a now well-established pattern, let me (re)warn (the few) unwary ‘Og readers that the links to Amazon.com and to Amazon.fr found on this blog are actually susceptible to earn me a monetary gain [from 4% to 8% on the sales] if a purchase is made by the reader ... [Read more...]

Displaying large regression models without overwhelming the reader can be challenging. I believe that forestplots are amazingly well suited for this. The plot gives a quick understanding of the estimates position in comparison to other estimates, while also showcasing the uncertainty. This project started with some minor tweaks to prof. ... [Read more...]

Fukushima is still a topic which gets headlines, and somewhere in a comment was a link to actual and historical radiation data: Fukushima prefecture radioactivity measurement map.  It takes a bit of time to load but then you have a map of the Fukushima region with current radiation levels at ... [Read more...]

The Thunder this season have already played some pretty exciting/anxiety-causing basketball.  Not just the excitement of watching new and old players return to the court, but the games seem to have been back-to-back nail-biting.  Peering arou... [Read more...]

I saved the data from the last post which shows the percentage of Republican voters in each county. In addition to that column, I also have figures from the 2010 census. This will show things like age, ethnicity, urbanization and home ownership. Those census figures show actual population counts, so they'll ... [Read more...]

I saved the data from the last post which shows the percentage of Republican voters in each county. In addition to that column, I also have figures from the 2010 census. This will show things like age, ethnicity, urbanization and home ownership. Those census figures show actual population counts, so they’... [Read more...]

R Interface for Teaching Kaitlin Thaney asked on Twitter last week about using Ramnath Vaidyanathan's new interactive R notebook 1 2 for teaching. Liking the look of interactive R notebook by @ramnath_vaidya. Any success stories in using to teach? http://t.co/wmVuFM2Rst (HT @_inundata)— Kaitlin Thaney (@kaythaney) July 9, 2013 Now, ... [Read more...]

I spent yesterday at the very enjoyable Big Data Summit held at the University of Illinois Research Park at the edge of the University of Illinois at Urbana-Champaign. campus. My (short) presentation was part of a panel session on R and Big Data... [Read more...]

Carrying on from the last post, I'm going to take a closer look at election results for the 2012 US presidential election in North Carolina. This state's 15 electoral votes went to the Republican, Mitt Romney. On the US electoral college map, that means the state shows up as red. As I ... [Read more...]

The problem with puzzles is that you keep it in your head for days, until you find an answer. Or at least some ideas about a possible answer. This is what happened to me a few weeks ago, when a colleague of mine asked me the following question : Consider points ... [Read more...]

You’ve probably heard about the t distribution. One good use for this distribution is as an alternative to the normal distribution that is more robust against outliers. But where does the t distribution come from? One intuitive characterization of the t is as a mixture of normal distributions. More ... [Read more...]

Dear diary, I spent a lot of my summer in the lab, and my fall has been mostly data analysis, with a little writing and a couple of courses thrown in there. Data analysis means writing code, and nowadays I do most of my work with the help of R. ... [Read more...]

Using Samatha So I decided to try out David Springates Samatha package for statically building this blog. If you decide to use it, be warned, right now it is a little rough around the edges, and needs some work. David created his own blog using it, and has been using ... [Read more...]

Mebane Faber posted another interesting blog post: Building a Simple Sector Rotation on Momentum and Trend that caught my interest. Today I want to show how you can test such strategy using the Systematic Investor Toolbox: Mebane thank you very much for sharing your great ideas. I would encourage readers ... [Read more...]

Recently, I was looking at some published research, and I became concerned that it looked strange. Firstly, it had results wildly different to other similar studies, and more exciting / publishable ones. So, I was looking through the original paper … Continue reading → [Read more...]