A short while ago I was contracted to write a short piece entitled “Introduction to Fractals”. The article can be found here. Admittedly it is hard to do justice to the topic in less than 1000 words. Both of the illustrations were created with R. Mandelbrot Set The Mandelbrot Set image ... [Read more...]

TableToLongForm automatically converts hierarchical Tables intended for a human reader into a simple LongForm Dataframe that is machine readable, hence enabling much greater utilisation of the data. It does this by recognising positional cues present in the hierarchical Table (which … Continue reading → [Read more...]

This was one headline in the USA Today I picked from the hotel lobby on my way to Pittsburgh airport and then Toronto this morning. The unusual pattern was about observing four U.S. mass murders happening within four days, “for the first time in at least seven years”. The ... [Read more...]

A horse with a crimson “6” displayed on either side of its girth processes to the parade ring. There are people milling about, looking over “Six” as well as the other entrants for the 2013 running of the St. Leger Stakes. Alongside Six stands a very short, wiry man dressed in a ... [Read more...]

Last quarter was a bit too busy to write some new blog post because of a new job. And changing the job often come along with changing the tools you work with. That was my way to Tableau. Tableau is one of the new stars in the BI/Analytics world ... [Read more...]

Having only ever played with Latent Dirichlet Allocation using gensim in python, I was very interested to see a nice example of this kind of topic modelling in R.  Whenever I see a really cool analysis done, I get the … Continue reading → [Read more...]

Piet Mondrian Composition with Red, Blue, Black, Yellow, and Gray (1921): An example draw from my simulation function: We're in the midst of planning our spring course on Empirical Research Methods, and as a result, I've found myself spending a lot of time thinking about some of the fist ideas in ... [Read more...]

I ran into this presentation on Statistical aspects of two-way cross-over studies by Ing. Helmut Schütz (http://bebac.at). He presented some code and referred to the bear package. The bear package is menu driven, which is not my thing. I had to try and do that in R ... [Read more...]

[This article was first published on Learning Data Science , and kindly contributed to R-bloggers]. (You can report issue about the content on this page here) Want to share [Read more...]

# The theoretical basis of classical consumer theory lies# in utility maximization. The idea is that consumers# make consumption decisions based on choosing a bundle # of goods that will maximize individual utility.# Despite this hypothesis being large... [Read more...]

I recently came across a very interesting idea at the The Problem with Market Neutral (and an Answer) post by Mebane Faber. Today I want to show how you can test such strategy using the Systematic Investor Toolbox: Mebane thank you very much for sharing this great observation and great ... [Read more...]

Revolution R Enterprise 7 is a major update to Revolution Analytics' flagship predictive analytics software. Not only does it include the latest release of Open Source R (providing compatability with more than 6,000 user-contributed packages), it also adds in-Hadoop and in-database predictive modeling with big data, new statistical capabilities, and drag-and-drop workflow ... [Read more...]

Just what you need - some more interesting reading! Al-Sadoon, M. M., 2013. Geometric and long run aspects of Granger causality. Mimeo., Universitat Pompeu Fabra. (Forthcoming in Journal of Econometrics.) Barnett, W. A. and I. Kalondo-Kanyama, 2013. Time-varying parameter in the almost ideal demand system and the Rotterdam model: Will the best ... [Read more...]

# Han (2012) in the paper "An Efficiency Balanced Information Criterion # for Item Selection in Computerized Adaptive Testing" proposes a method# of evaluating potential items based on expected item potential information # as a function of maximum pote... [Read more...]

## geom_smooth: method="auto" and size of largest group is <1000, so using<br>## loess. Use 'method = x' to change the smoothing method.<br>

I remember my dad telling me that when he was at Northwestern in the mid-70s, the team was essentially winless. As a small consolation, he remembered that the football team had actually been full of good students. Some time ago, I stumbled across nflcombineresults.com. Among other measures, ... [Read more...]

In my previous post about estimating the Percolation Threshold on a square lattice, I only considered flow from a given cell to its four nearest neighbours. It is a relatively simple matter to extend the recursive flow algorithm to include other configurations as well. Malarz and Galam (2005) considered the problem ... [Read more...]

This past summer when the twin cities R user group was starting to get back up and running, I offered to present on some R related things that I was working on. One thing I was working on was a part of my last post. In a response to discussing ... [Read more...]