I was once told that the reason that such a shape was so commonly used for aeroplane wings was merely that then one could study it mathemtically by just employing the Zhoukowski transformation. I hope that this is not true! (R. Penrose, “The Road to Reality”, p.150) Penrose here talks about a complex holomorphic mapping 
In Efficient Frontier of Funds and Allocation Systems, I had hoped to start exploring how a frontier can potentially be created with only one asset, or how an even more efficient frontier could be created with assets and also systems on those assets.&n...
In this short post I take a look at how to use R and ggplot2 to visualize effect sizes (Cohen’s d) and how to shade the overlapping area of two distributions.
This afternoon, I will be giving a two-hour talk at McGill on quantiles, quantile regressions, confidence regions, bagplots and outliers. Before defining (properly) quantile regressions, we will mention regression on (local) quantiles, as on the gr...
Ted Harding posed an interesting puzzle challenge on the r-help mailing list recently. Here's the puzzle: Take the numbers 1, 2, 3, etc. up to 17. Can you write out all seventeen numbers in a line so that every pair of numbers that are next to each other, adds up to give a square number? You can figure out...
This post describes some of the simulation results which I obtained with the GAMBoost package. The aim of these simulations is to get a feel what I should tune and what I should not tune with GAMBoost. SetupIn the GAMBoost package one can tune qui...
R
There are often times when it is useful to create an individual level dataset from aggregated data (such as a table). While this can be done using the expand.table() function within the epitools package, it is also straightforward to do directly within R.
Imagine that instead of the individual level data, we had only the 2x2 table for the...
Today I received confirmation that the delayed fifth volume in the Developments in Palaeoenvironmental Research series has been published. The book is titled Data Handling and Numerical methods, though it covers more of the latter and, IMHO, is far more interesting than … Continue reading →
I've made some updates to the Emacs Starter Kit for the Social Sciences. The kit builds on Phil Hagelberg's original and Eric Schulte's org-mode version, and incorporates some packages and settings that are particularly useful for the social sciences. ...
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
