# Posts

### September 13, 2014

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8:33 PM | Sum of geometric means

Let xn be a sequence of non-negative numbers. Then the sum of their running geometric means is bounded by e times their sum. In symbols The inequality is strict unless all the x‘s are zero, and the constant e on the right side is optimal. Torsten Carleman proved this theorem in 1923.

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For a while, the Science Museum has been forming groups and making noises and tickling rich people with the aim of working out how they’re going to update their rather neglected maths hall. Yesterday they made an unexpectedly positive announcement: they’ve been given £5 million by rich people David and Claudia Harding, and Dame Zaha Hadid has drawn up a... Read more »

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Here are excerpts from the speech of Arvind Gupta at his official installation as UBC’s 13th president. Canada’s post-secondary system should take notice. “We recognize UBC as a Place of Mind, but also as a place of shared cultures, traditions, and … Continue reading →

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via Cinque cose belleMia sorella mi ha ricordato che oggi è il Roald Dahl Day, così ecco la recensione di un romanzo sorprendente, inedito in Italia.Se siete uno di quegli adulti che amano Roald Dahl per le sue storie per bambini, se siete uno di quegli adulti che ritiene Il GGG il più bel libro mai scritto in assoluto, allora state lontani da Lo zio Oswald: potrebbe non piacervi.Il romanzo di Dahl, fino a qualche tempo fa ancora inedito in Italia, aggiunge un nuovo
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2:25 PM | The naming of America – Redux

This is a brief addenda to my previous naming of America post, as my copy of Peter Macdonald’s Cabot & The Naming of America: Dawn of Arrival, Newfoundland, June 1497 has finally arrived; remaindered, it cost all of £0.01! (p&p … Continue reading →

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1:08 PM | Aunt Pythia’s advice

Do you know what Aunt Pythia has been occupied with recently? Yes, you guessed it, she has a fantabulous new knitting pattern and she just can’t get enough of it. Here’s a recent work-in-progress pic: I hope you know how much Aunt Pythia must love you considering how hard it was to tear herself away […]

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Fernando Martel Garcia writes: So I am applying for a DC driver’s license and needed a translation of my Spanish license to show to the DMV. I go to http://www.onehourtranslation.com/ and as I prepare to pay I see a familiar face in the bottom banner: It appears Stapel is one of their “over 15,000 dedicated […]
The post He just ordered a translation from Diederik Stapel appeared first on Statistical Modeling, Causal Inference, and Social Science.

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8:53 AM | GeoGebra in 3D: ThreeoGebra!

GeoGebra, the Aperiodical’s official Favourite Thing for Messing About With Geometry, has just bumped up to version 5. With that bigger number comes another dimension – GeoGebra now supports three-dimensional geometry! This stuff has been in the works for a long time – since 2008, apparently – and it looks like GeoGebra 5 hasn’t quite reached... Read more »

### September 12, 2014

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10:14 PM | available dark [book review]

“Paved roads had long ago surrended to gravel tracks that disappeared into a desert of snow covered lava. Black spires like a forest of charred trees blotted out the stars near the horizon.” This is the last book I read from my Amazon package: Available Dark by Elizabeth Hand. I cannot remember how I came […]

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7:36 PM | Leggere Lolita a Teheran

Un po' di anni fa mi parlarono molto bene di questo libro ma non lo presi subito, e me ne dimenticai. L'anno scorso mi ritornò in mente e lo misi nella mia lista dei desideri: desiderio realizzato!Il libro inizia con un incontro segreto, un seminario letterario al quale partecipano 7 donne. Viene organizzato dalla protagonista (e scrittrice) del libro a casa sua, dove possono sentirsi libere di non coprirsi con il velo e sfoggiare colori e accessori, sentirsi libere di essere sé
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2:35 PM | Another one bites the dust

This is a sort of footnote to my last post in which I criticised science writer Tim Radford for propagating myths about the reception of heliocentricity in the sixteenth-century. Now a second truly legendary astronomer and science writer, John Gribbin, … Continue reading →

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2:23 PM | What is the purpose of a poem?

OK, let’s take a break from blogging about economics. OK, I haven’t actually been blogging so much about econ lately, but it just happens that I’m writing this on 19 July, a day after poking a stick into the hornet’s nest by posting “Differences between econometrics and statistics: From varying treatment effects to utilities, economists […]
The post What is the purpose of a poem? appeared first on Statistical Modeling, Causal Inference, and Social Science.

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12:18 PM | 3,000 posts and 1,000,000 views so far…

As the ‘Og went over its [first] million views and 3,000 posts since its first post in October 2008, the most popular entries (lots of book reviews, too many obituaries, and several guest posts): In{s}a(ne)!! 9,330 “simply start over and build something better” 8,514 George Casella 6,712 About 4,853 Bayesian p-values 4,468 Sudoku via simulated […]

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11:00 AM | What’s next for mathbabe?

The Colombia J-School program that I have been directing, The Lede Program in Data Journalism, has wound down this past week and in four days my 6-month contract with Columbia will end. I’ve had a fantastic time and I am super proud of what we accomplished this past summer. The students from the program are awesome and […]

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One of the exciting things in reading philosophy, its history in particular, is experiencing the tension between different schools of thought. This excitement turns to beauty if a clear synthesis emerges to reconcile the conflicting ideas. In the middle to late 18th century, as the Age of Enlightenment was giving way to the Romantic era, […]

Post, E.L. (1936). Finite combinatory processes -- formulation 1., Journal of Symbolic Logic, 1 (3) 103-105.

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1:25 AM | mysterious shiny things

(Disclaimer: I’m new to Shiny, and blog posts, but I know something about geography.) In the Shiny gallery, take a look at 2001 versus 2002. Something funny happens to Switzerland (and other European countries), in terms of the legend, it moves from Europe to the Middle East. Also, the legend color scheme switches. […]
The post mysterious shiny things appeared first on Statistical Modeling, Causal Inference, and Social Science.

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12:09 AM | A data scientist is…

My wife sent me this tweet by David M. Wessel this morning. It’s a photograph of a presentation slide giving three definitions of data scientists: “A data scientist is a statistician who lives in San Francisco. Data science is statistics on a Mac. A data scientist is someone who is better at statistics than any software […]

### September 11, 2014

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10:14 PM | my life as a mixture [BAYSM 2014, Wien]

Next week I am giving a talk at BAYSM in Vienna. BAYSM is the Bayesian Young Statisticians meeting so one may wonder why, but with Chris Holmes and Mike West, we got invited as more… erm… senior speakers! So I decided to give a definitely senior talk on a thread pursued throughout my career so far, […]

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There’s a new intro to Bayes in town. Michael Lee and Eric-Jan Wagenmaker. 2014. Bayesian Cognitive Modeling: A Practical Course. Cambridge Uni. Press. This book’s a wonderful introduction to applied Bayesian modeling. But don’t take my word for it — you can download and read the first two parts of the book (hundreds of pages […]
The post Bayesian Cognitive Modeling Examples Ported to Stan appeared first on Statistical Modeling, Causal Inference, and Social
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1:22 PM | One-tailed or two-tailed

This image of a two-tailed lizard (from here, I can’t find the name of the person who took the picture) never fails to amuse me. But let us get to the question at hand . . . Richard Rasiej writes: I’m currently teaching a summer session course in Elementary Statistics. The text that I was […]
The post One-tailed or two-tailed appeared first on Statistical Modeling, Causal Inference, and Social Science.

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12:18 PM | O’Bayes 2015: back in València

The next O’Bayes meeting (more precisely the International Workshop on Objective Bayes Methodology, O-Bayes15), will take place in València, Spain, on June 1-4, 2015. This is the second time an O’Bayes conference takes place in València, after the one José Miguel Bernardo organised in 1998 there. The principal objectives of O-Bayes15 will be to facilitate […]

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This is a guest post by Marc Joffe, a former Senior Director at Moody’s Analytics, who founded Public Sector Credit Solutions in 2011 to educate the public about the risk – or lack of risk – in government securities. Marc published an open source government bond rating tool in 2012 and launched a transparent credit scoring platform for […]

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A team led by Thomas Hales has announced a formal proof of the Kepler conjecture – one of the oldest problems in geometry – which states that no packing of equally sized spheres in 3-dimensional space is more efficient than the face-centred cubic packing (pictured right), or hexagonal close packing. These packings are both around 74% efficient... Read more »

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This post is a review of the “GENERALIZED DOUBLE PARETO SHRINKAGE” Statistica Sinica (2012) paper by Armagan, Dunson and Lee. Consider the regression model \(Y=X\beta+\varepsilon\) where we put a generalized double pareto distribution as the prior on the regression coefficients \(\beta\). The GDP distribution has density $$\begin{equation} f(\beta|\xi,\alpha)=\frac{1}{2\xi}\left( 1+\frac{|\beta|}{\alpha\xi} \right)^{-(\alpha+1)}. \label{} \end{equation}$$ GDP as Scale […]
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### September 10, 2014

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10:14 PM | Scottish polls…

As much as I love Scotland, or because of it, I would not dream of suggesting to Scots that one side of the referendum sounds better than the other. However, I am rather annoyed at the yoyo-like reactions to the successive polls about the result, because, just like during the US elections, each poll is […]

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Guest post by Bruce Bartlett I recently put an article on the arXiv: Bruce Bartlett, Quasistrict symmetric monoidal 2-categories via wire diagrams. It's about Chris Schommer-Pries's recent strictification result from his updated thesis, that every symmetric monoidal bicategory is...

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7:57 PM | The Book Bucket Challenge

This idea came from a thing that is now really famous on Facebook and it is called #TheBookBucketChallenge. This is about making a list of 10 books that influenced you, that changed your way of thinking, that are the best … Continue reading →

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4:17 PM | Apologies

On behalf of the M-Phi contributors, I want to sincerely apologize to our readers for the misguided and inappropriate post that was online at M-Phi for four days (now taken down, as well as all other posts referencing the Oxford events). The moderation structure of the blog was such that none of us could do anything to take it down, except for pleading with the author to do so.The structure and moderation of the blog will change completely now; Jeffrey Ketland will no longer be a contributor
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3:40 PM | I expected better of Tim Radford

Tim Radford is a science writer who works for The Guardian newspaper. In fact many people consider him the best British science writer of the current crop, not without a certain amount of justification. Because of this I was, as … Continue reading →

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In effetti questa è (o dovrebbe essere) la versione estesa di una conferenza di Philip K. Dick alla convention fantascientifica di Metz, in Francia, nel 1977. Non sono riuscito a trovare trascrizioni dell'intervento realmente fatto dallo scrittore a Metz, ma il video (via Open Culture) è abbastanza differente (non troppo rispetto ai contenuti) rispetto al testo (archive.org) successivamente pubblicato sulla Philip K. Dick Society Newsletter #27.Innanzitutto Dick esprime l'idea
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Susskind L. (1995). The world as a hologram, Journal of Mathematical Physics, 36 (11) 6377. DOI: http://dx.doi.org/10.1063/1.531249

Bousso R. (2002). The holographic principle, Reviews of Modern Physics, 74 (3) 825-874. DOI: http://dx.doi.org/10.1103/revmodphys.74.825

Bekenstein J. (2008). Bekenstein-Hawking entropy, Scholarpedia, 3 (10) 7375. DOI: http://dx.doi.org/10.4249/scholarpedia.7375

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