Mandelbrot and Akaike: from taxonomy to smooth runways (pioneering work in fractals and self-similarity)

October 16, 2010
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Mandelbrot on taxonomy (from 1955; the first publication about fractals that I know of): Searching for Mandelbrot on the blog led me to Akaike, who also recently passed away and also did interesting early work on self-similar stochastic proces...

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Benoit Mandelbrot (the Father of Fractals) dead at 85

October 16, 2010
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Benoit Mandelbrot (the Father of Fractals) dead at 85

Nicholas Taleb and Recent tweets indicate that Benoit Mandelbrot has died at age 85.  Mandelbrot was a French and American mathematician, best known as the father of fractal geometry.  His official biography at Yale does n...

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Benoit Mandelbrot (the Father of Fractals) dead at 85

October 16, 2010
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Benoit Mandelbrot (the Father of Fractals) dead at 85

Nicholas Taleb and Recent tweets indicate that Benoit Mandelbrot has died at age 85.  Mandelbrot was a French and American mathematician, best known as the father of fractal geometry.  His official biography at Yale does n...

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Busting gay stereotypes with data

October 15, 2010
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Busting gay stereotypes with data

As a gay guy, you sometimes have to put up with some pretty offensive stereotypes that get thrown your way by extremists in the community and the media. These stereotypes are usually deployed in the form of anecdotes about how gay people are "promiscuous" or "corrupting". These misrepresentative anecdotes have serious consequences, not just in the continued denial of...

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R 2.12.0 released

October 15, 2010
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As announced today, The new R 2.12.0 is now available in source form, and you'll soon be able to download R as an installable binary for Windows, Mac and Linux from your local CRAN mirror. In the meantime, if you're not building R yourself you can check out the list of new features in the NEWS file. As usual,...

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Are class representatives twice as satisfied?

October 15, 2010
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Are class representatives twice as satisfied?

So Agnes asked (via Facebook), looking at my previous post, http://stevepowell99.posterous.com/which-parents-are-satisfied-with-their-childs, if class representatives are more satisfied than other parents? This picture shows that they are: the parents with Rep=TRUE, i.e. the representatives, are also more satisfied, especially in schools where parents are generally less satisfied. So perhaps this explains away the effect in the

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Are class representatives twice as satisfied?

October 15, 2010
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Are class representatives twice as satisfied?

So Agnes asked (via Facebook), looking at my previous post, http://stevepowell99.posterous.com/which-parents-are-satisfied-with-their-childs, if class representatives are more satisfied than other parents? This picture shows that they are: ...

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Margin of error, and comparing proportions in the same sample

October 15, 2010
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Margin of error, and comparing proportions in the same sample

I recently tried to answer a simple question, asked by @adelaigue. Actually, I thought that the answer would be obvious... but it is a little bit more compexe than what I thought. In a recent pool about elections in Brazil, it was mentionned in a ...

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Prediction with Multilevel Regression Models, and Pizza

October 15, 2010
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The Meetup phenomenon, which is now substantial and longstanding enough to be more of a cultural change than a flash in the pan, continues to impress me. Even more so than tools like LinkedIn, Meetups have changed the nature of professional networking, making it more informal, diverse, and decentralized. Last night, statistics consultant (and cheap

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Shravan Vasishth’s Slog (Statistics blog) 2010-10-15 06:47:00

October 15, 2010
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I foolishly tried to convert a matrix M to a vector using vector:vector(M)But this is done column wise, so that adjacent row items end up non-adjacent.The right way to do this seems to be:library(data)unmatrix(M, byrow=TRUE)

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Shravan Vasishth’s Slog (Statistics blog) 2010-10-15 06:47:00

October 15, 2010
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I foolishly tried to convert a matrix M to a vector using vector:vector(M)But this is done column wise, so that adjacent row items end up non-adjacent.The right way to do this seems to be:library(data)unmatrix(M, byrow=TRUE)

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R 2.12.0 is released!

October 15, 2010
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R 2.12.0 is released!

The new R 2.12.0 is out! Get the source code from here. Take a look at these posts for some miscellaneous advices to make the upgrade easier. Also this thread on stackoverflow can be of some value. Feel free to contribute with suggestions about how to ...

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R 2.12.0 is released!

October 15, 2010
By
R 2.12.0 is released!

The new R 2.12.0 is out! Get the source code from here. Take a look at these posts for some miscellaneous advices to make the upgrade easier. Also this thread on stackoverflow can be of some value. Feel free to contribute with suggestions about how to ...

Read more »

Rcpp 0.8.7

October 15, 2010
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With the scheduled R release of version 2.12.0 this morning, we have just uploaded version 0.8.7 of Rcpp to CRAN; Debian will follow shortly once the autobuilders have processed R 2.12.0 This Rcpp release depends on R 2.12.0 as two things have cha...

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Nightlights: First Principles

October 15, 2010
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Nightlights: First Principles

With the publication of Hansen2010 forthcoming it is critical to examine the subject afresh. The global temperature index product from NASA is known as GISSTEMP .GISSTEMP, like the temperature index from Hadley/CRU and NCDC attempts to estimate the average temperature of the globe using historical data archived in the GHCN ( Global Climate Historical Network)

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The S3 OOP system

October 15, 2010
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R currently supports two internal OOP systems (S3 and S4), and several others as add-on packages, such as R.oo, and OOP. S3 is easy to use but not reliable enough for large software projects. The emphasis of the S3 system was on generic functions and polymorphism. It’s a function centric system which is different to class centric system like JAVA.

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The S3 OOP system

October 15, 2010
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R currently supports two internal OOP systems (S3 and S4), and several others as add-on packages, such as R.oo, and OOP. S3 is easy to use but not reliable enough for large software projects. The emphasis of the S3 system was on generic functions and polymorphism. It’s a function centric system which is different to class centric system like...

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Nightlights: cool data, bad geocoding

October 14, 2010
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Nightlights: cool data, bad geocoding

A global source of population density has been on my low-priority wish list for some time, so I was very excited when I found Steve Mosher’s work with the Nighlights data set. “Nightlights” refers to the artificial lights seen from space at night. Astronomers call it “light pollution” which is pretty accurate since it’s decidedly

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Which parents are satisfied with their child’s education? Those who know their class representative well. Especially in poor schools.

October 14, 2010
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Which parents are satisfied with their child’s education? Those who know their class representative well. Especially in poor schools.

Another result from our OSI / ESP survey of nearly 11000 parents in ten countries. Dots are individual parents. The y-axis is individual parents’ overall satisfaction with their children’s education. Red dots are parents who know their parent representatives well, blue dots are parents who do not; i.e. colour is mapped to the variable par.rep.1

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Which parents are satisfied with their child’s education? Those who know their class representative well. Especially in poor schools.

October 14, 2010
By
Which parents are satisfied with their child’s education? Those who know their class representative well. Especially in poor schools.

Another result from our OSI / ESP survey of nearly 11000 parents in ten countries. Dots are individual parents.The y-axis is individual parents' overall satisfaction with their children's education. Red dots are parents who know the...

Read more »

Liquidity Premium vs Liquidity of Corporate Bonds

Liquidity Premium vs Liquidity of Corporate Bonds

All else equal, investors should require higher returns on assets whose liquidity is lower, in other words, investors demand a higher expected return, and hence larger liquidity premium, by holding a less liquidity asset. Risk & return co-exist.Is this really true for corporate bonds? I run a simple regression using R to test my data, where US corporate bonds...

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How to build a world-beating predictive model using R

How to build a world-beating predictive model using R

Many modern data analysis problems in both industry and academia involve building a model that can predict the future based on historical variables. The 2009 KDD Cup was an international data mining competition devoted to this type of problem, where … Continue reading →

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Boxplots or raw data graphs?

October 14, 2010
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Boxplots or raw data graphs?

We recently had a dilemma for an OSI publication about the design for the graphs. There will be dozens of these graphs showing the mean score on a given variable for nearly 11000 parents from 10 countries. This example is for household wealth which has values ranging from 0 to 16. These are the three

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Boxplots or raw data graphs?

October 14, 2010
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Boxplots or raw data graphs?

We recently had a dilemma for an OSI publication about the design for the graphs. There will be dozens of these graphs showing the mean score on a given variable for nearly 11000 parents from 10 countries. This example is for household wealt...

Read more »

R is Hot: Part 2

October 14, 2010
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This is Part 2 of a five-part article series, with new parts published each Thursday. You can download the complete article from the Revolution Analytics website. Critical Mass and Going Viral R was created in 1993 by Ross Ihaka and Robert Gentleman at the University of Aukland in New Zealand. It’s called R for the simple reason that both...

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Postdoc position in computational Bayesian statistics

October 14, 2010
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Postdoc position in computational Bayesian statistics

Here is an announcement I received that should interest potential postdocs (willing to come to Paris). The location is on the Orsay campus, south of Paris. In the framework of the ANR-funded Metacoli project which aims at identifying the metabolic underpinnings of the lifestyle diversity in the E. coli species, Genoscope (the genomics institute of

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Kuwait Airport

October 14, 2010
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Kuwait Airport

  Kuwait International airport. Giss has it as nightlights =0, so do I. By looking at comparisons of nightlights with the station centered and a static google map with the station centered, there are mismatches between GISS and Me and between Nightlights and the  world. Subtle shift here and there. Annoying. Also, you can see

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Nightlights, Contours, and Rgooglemap

October 14, 2010
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Nightlights, Contours, and Rgooglemap

I am continuing the investigation of nightlights using some additional packages from Cran. Here we add Rgooglemaps to the mix. Rgooglemaps is a neat tool that gives you a simple ( needs better docs) interface to the static map server. Perhaps, I’ll modify the code to my likeing, so For now I use it as

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R wanted for an intern at Barron’s

October 13, 2010
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R/SQL/scripting, oodles of data, a willing outlet for write-ups. Any takers? Do some good. Intern at Barron’s, the New York financial publication with a decades-long tradition of investigative journalism and a more recent commitment to data analytic exposure of fraud in finance, business and healthcare. Bring us your zeal and your data munging skills and

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