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# Posts

### April 19, 2014

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Last month, I ordered several books on amazon,  taking advantage of my amazon associate gains, and some of them were suggested by amazon algorithms based on my recent history. As I had recently read books involving thieves (like Giant Thief, or Broken Blade and the subsequent books), a lot of titles involved thieves or thievery […]
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As I promised earlier, here is the video for my talk on "structures in solution spaces" at the Conference on Meaningfulness and Learning Spaces last February.It was a wide-ranging talk, about learning spaces, distributive lattices and Birkhoff's representation theorem for them, rectangular cartograms, antimatroids, the 1/3-2/3 conjecture for partial orders and antimatroids, partial cubes, and flip distance in binary trees and point sets. It was also about an hour long, so don't watch unless you […]
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Here the monotonicity of the EM algorithm is established. $$f_{o}(Y_{o}|\theta)=f_{o,m}(Y_{o},Y_{m}|\theta)/f_{m|o}(Y_{m}|Y_{o},\theta)$$ $$\log L_{o}(\theta)=\log L_{o,m}(\theta)-\log f_{m|o}(Y_{m}|Y_{o},\theta) \label{eq:loglikelihood}$$ where $$L_{o}(\theta)$$ is the likelihood under the observed data and $$L_{o,m}(\theta)$$ is the likelihood under the complete data. Taking the expectation of the second line with respect to the conditional distribution of $$Y_{m}$$ given $$Y_{o}$$ and […]
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Someone who doesn’t want his name shared (for the perhaps reasonable reason that he’ll “one day not be confused, and would rather my confusion not live on online forever”) writes: I’m exploring HLMs and stan, using your book with Jennifer Hill as my field guide to this new territory. I think I have a generally […]The post Index or indicator variables appeared first on Statistical Modeling, Causal Inference, and Social Science.
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Filed under: pictures, Travel, Wines Tagged: Belgian beer, Belgium, brewery, Leuven, MCQMC2014, Stella Artois
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Great to be here, and glad you came. Please hop on the nerd advice column bus for another week of ridiculous if not damaging guidance from yours truly, Aunt Pythia. And please, after enjoying today’s counsel to other poor, unsuspecting fools: think of something to ask Aunt Pythia at the bottom of the page! By the way, […]
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By the way, sometime yesterday this blog received its millionth visit.
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For something I’m writing I looked up a newspaper article I was interviewed in in, from June 7, 1989.  Here’s what I had to say: Ellenberg on mathematics: “I always think of it — this is kind of crazy — as a zoo. There are a million different mathematical objects. They are like animals. Some […]

### April 18, 2014

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The English title of this 2007 book of Murakami is “What I talk about when I talk about running”. Which is a parody of Raymond Carver’s collection of [superb] short stories, “What we talk about when we talk about love”. (Murakami translated the complete œuvres of Raymond Carver in Japanese.) It is a sort of diary […]
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Describes Kelly's "Elementary observations on 2-categorical limits" and the general theory of weighted limits and colimits, which are described here in a special case.
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Not even going to link to this article but this is so magnificently dumb I had to share it with someone. As everyone knows by now, GM’s entry into the electric car market–the Chevy Volt–costs $41,000 before tax breaks. After the tax breaks, you can happily drive one off the lot for$33,000 … if you […]
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Someone writes: Suppose I have two groups of people, A and B, which differ on some characteristic of interest to me; and for each person I measure a single real-valued quantity X. I have a theory that group A has a higher mean value of X than group B. I test this theory by using […]The post One-tailed or two-tailed? appeared first on Statistical Modeling, Causal Inference, and Social Science.
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I recently saw a short list of advice for new assistant professors by Chris Blattman [Link]. Chris is an Assistant Professor of Political Science & International and Public Affairs at Columbia University (soon to be tenured). His list is summarized below. Go to his blog post for the full discussion: Learn to say no to new […]
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Today, I am leaving Paris for a 8 day stay in Iceland! This is quite exciting, for many reasons: first, I missed the AISTATS 2013 last year as I was still in the hospital;  second, I am giving a short short tutorial on ABC methods which will be more like a long (two hours)  talk; […]
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A few weeks ago I mentioned that I’m the Program Director for the new Lede Program at the Columbia Graduate School of Journalism. I’m super excited to announce that I’ve found amazing faculty for the summer part of the program, including: Jonathan Soma, who will be the primary instructor for Basic Computing and for Algorithms Dennis […]
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Some good pre-publication reviews are coming in!  From Kirkus: Witty and expansive, Ellenberg’s math will leave readers informed, intrigued and armed with plenty of impressive conversation starters. And Booklist (not available online, unfortunately:) Relying on remarkably few technical formulas, Ellenberg writes with humor and verve as he repeatedly demonstrates that mathematics simply extends common sense. He manages to […]
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This evening something reminded me of the following line from Rudyard Kipling’s famous poem If: … If all men count with you, but none too much … It would be good career advice for a mathematician to say “Let all…Read more ›
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Originally posted on TED Blog:Student Pierre Hirschler gives a TED-Ed Club presentation, exploring math as a universal language. In New York City, it’s common to hear ten different languages just on your walk to work in the morning. For the students…

### April 17, 2014

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Daniel Simpson gave a seminar at CREST yesterday on his recently arXived paper, “Penalising model component complexity: A principled, practical  approach to constructing priors” written with Thiago Martins, Andrea Riebler, Håvard Rue, and Sigrunn Sørbye. Paper that he should also have given in Banff last month had he not lost his passport in København airport…  […]
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The Global Hunger Index was first published in 2006 by the International Food Policy Research Institute and the NGO Welthungerhilfe. In 2007, Concern worldwide joined them. Since then, the Index reports every year the evolution of the hunger situation worldwide and focus on a given topic. How is it calculated? And what is hunger? How are we connected ? What can be done? To learn more, read the article below.
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At a lose end on Good Friday or Easter Monday? Read up on the best history of science bloggage from the last thirty days gathered from the far reaches of cyberspace for your pleasure. Lisa Smith (@historybeagle) has put together … Continue reading →
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Nelson Villoria writes: I find the multilevel approach very useful for a problem I am dealing with, and I was wondering whether you could point me to some references about poolability tests for multilevel models. I am working with time series of cross sectional data and I want to test whether the data supports cross […]The post If you get to the point of asking, just do it. But some difficulties do arise . . . appeared first on Statistical Modeling, Causal Inference, and Social Science.
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A paper written by Martin Gilens and Benjamin Page and entitled Testing Theories of American Politics: Elites, Interest Groups, and Average Citizens has been recently released and reported on (h/t Michael Crimmins) that studies who has influence on policy in the United States. Here’s an excerpt from the abstract of the paper: Multivariate analysis indicates that economic elites […]

### April 16, 2014

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Randal Douc, Florian Maire, and Jimmy Olsson recently arXived a paper on the use of Markov chain Monte Carlo methods for the sampling of mixture models, which contains the recourse to Carlin and Chib (1995) pseudo-priors to simulate from a mixture distribution (and not from the posterior distribution associated with a mixture sampling model). As […]
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Non voglio fare concorrenza alla splendida spiegazione di Amedeo o a quella tecnica di Corrado, ma mia sorella, leggendo il post di pancia scritto nella sera dell'annuncio di BICEP2, ha candidamente confessato di non aver capito cosa era accaduto quel giorno. E allora proviamoci, a raccontarlo. (da The Cartoon History of the Universe #1 di Larry Gonick)C'era una volta un'idea di universo, che era la Terra al centro, quindi il Sole, la Luna e gli altri pianeti e sullo sfondo le stelle fisse, […]

Hubble E. (1929). A relation between distance and radial velocity among extra-galactic nebulae, Proceedings of the National Academy of Sciences, 15 (3) 168-173. DOI:

Gamow G. (1948). The Evolution of the Universe, Nature, 162 (4122) 680-682. DOI:

Alpher R.A. & Herman R. (1948). Evolution of the Universe, Nature, 162 (4124) 774-775. DOI:

Alpher R., Bethe H. & Gamow G. (1948). The Origin of Chemical Elements, Physical Review, 73 (7) 803-804. DOI:

Peebles P.J.E., Schramm D.N., Turner E.L. & Kron R.G. (1994). The Evolution of the Universe, Scientific American, 271 (4) 52-57. DOI:

McLeish T.C.B., Bower R.G., Tanner B.K., Smithson H.E., Panti C., Lewis N. & Gasper G.E.M. (2014). History: A medieval multiverse, Nature, 507 (7491) 161-163. DOI:

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#MIT #design #furniture #technology #Milano Transform is a magical, modular furniture developed by MIT: The work is comprised of three dynamic shape displays that move more than one thousand pins up and down in realtime to transform the tabletop into a dynamic tangible display. The kinetic energy of the viewers, captured by a sensor, drives the wave motion represented by the dynamic pins.The motion design is inspired by the dynamic interactions among wind, water and sand in nature, […]
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Congratulations to the newly selected NIMBioS postdoctoral fellows arriving this summer. Jake Ferguson is currently a doctoral student in biology at the Univ. of Florida. Ferguson’s project at NIMBioS will be to model the role of seasonality of ecological populations. … Continue reading →
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For those interested in visiting Toulouse at the end of the summer for a French speaking conference in Probability and Statistics, the Modélisation-Aléatoire-Statistique branch of SMAI (the French version of SIAM) is holding its yearly conference. The main theme this year is “High dimension phenomena”, but a large panel of the French research in Probability […]
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People appear to love list. The Internet is full of lists. The 10 most popular dog breeds, the 10 biggest waves ever ridden by a surfer, the 10… you get the idea. The lists very often have ten entries, it’s … Continue reading →
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Prakash Nayak writes: I work as a musculoskeletal oncologist (surgeon) in Mumbai, India and am keen on sarcoma research. Sarcomas are rare disorders, and conventional frequentist analysis falls short of providing meaningful results for clinical application. I am thus keen on applying Bayesian analysis to a lot of trials performed with small numbers in this […]The post Looking for Bayesian expertise in India, for the purpose of analysis of sarcoma trials appeared first on Statistical […]