# Posts

### June 29, 2015

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11:46 PM | A note from John Lott

The other day, I wrote: It’s been nearly 20 years since the last time there was a high-profile report of a social science survey that turned out to be undocumented. I’m referring to the case of John Lott, who said he did a survey on gun use in 1997, but, in the words of Wikipedia, […]
The post A note from John Lott appeared first on Statistical Modeling, Causal Inference, and Social Science.

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Radford shared with us this probability puzzle of his from 1999: A couple you’ve just met invite you over to dinner, saying “come by around 5pm, and we can talk for a while before our three kids come home from school at 6pm”. You arrive at the appointed time, and are invited into the house. […]
The post God is in every leaf of every probability puzzle appeared first on Statistical Modeling, Causal Inference, and Social Science.

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1:00 PM | On deck this week

Mon: God is in every leaf of every probability puzzle Tues: Where does Mister P draw the line? Wed: Recently in the sister blog Thurs: Humility needed in decision-making Fri: “Why should anyone believe that? Why does it make sense to model a series of astronomical events as though they were spins of a roulette […]
The post On deck this week appeared first on Statistical Modeling, Causal Inference, and Social Science.

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At the teaching blog, a follow-up to the language of Eureka post using the same lesson:Eureka Math Tips for Parents -- worst SAT prep question everHere's the offending passage this time.[And before you ask, the answer is no, a rectangle and a triangle can't have corresponding parts.]I have lots more material -- hell, that same page had a different problem that screwed up by omitting the AAA similarity theorem -- but I think that we've already uncovered an unacceptable number of major […]

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11:25 AM | Data mining children’s data

I was interviewed for an article entitled No Child Left Un-Mined? Student Privacy At Risk In The Age Of Big Data by journalist Farai Chideya, who writes for The Intercept along with Glenn Greenwald and other impressive people. Here’s the article, I think it came out pretty well and I’d be grateful for your thoughts.

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9:13 AM | 일본 동경대학(도쿄대) 박사과정 입시 수험기

오늘로 도쿄대학(東京大学) 수리과학연구과 박사과정 입시 끝! 이 우편물 하나 받는데 정말 많은 시간 걸렸다. 오랜만에 이 폴더가 업데이트 되는군… 이번에도 그간의 일정과 주고받았던 메일들을 기반으로 이번에도 수험기를 작성해 본다. 일단 학교를 선정해야 하는데… 석사를 간사이 지방에서 한지라 교토대학(京都大学)과 오사카대학(大阪大学)은 … Continue
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In these previous posts, we explored whether the cut polytope can be expressed as the linear projection of a polytope with a small number of facets (i.e., whether it has a small linear programming extended formulation). For many cut problems, semi-definite programs (SDPs) are able to achieve better approximation ratios than LPs. The most famous […]

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Gelman sums up the reasons why there is a crisis in experimental research in our time. The journal publication process fails to catch fake research (let alone bad research), and the new media prefer sensationalist headlines over good science. Many researchers are worrying about false positive results and research that are not reproducible. Read it all here in our debut column Statbusters for the Daily Beast.

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5:00 AM | Introducing StataStan

Thanks to Robert Grant, we now have a Stata interface! For more details, see: Robert Grant’s Blog: Introducing StataStan Jonah and Ben have already kicked the tires, and it works. We’ll be working on it more as time goes on as part of our Institute of Education Sciences grant (turns out education researchers use […]
The post Introducing StataStan appeared first on Statistical Modeling, Causal Inference, and Social Science.

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Learning in High Dimensions with Projected Linear Discriminants by Robert Durrant The enormous power of modern computers has made possible the statistical modelling of data with dimensionality that would have made this task inconceivable only decades ago. However, experience in such modelling has made researchers aware of many issues associated with working in high-dimensional domains, collectively known as `the curse of dimensionality', which can confound practitioners' desires to
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Following up on Friday's The Unreasonable Effectiveness of Random Projections in Computer Science here are two series of slides: Learning with Random Projections by Ata Kaban. The outline of the slides features the following subject;Introduction to compressive learningCompressive classificationCompressive regressionEnsembles And earlier, a tutorial for Random Projections for Machine Learning and Data Mining: Theory & Applications from Bob Durrant and Ata Kaban. (Handouts (6
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Here is an interesting workshop organized by Ata Kaban The 3rd International Workshop on High Dimensional Data Mining (HDM’15)In conjunction with the IEEE International Conference on Data Mining (IEEE ICDM 2015)14 November 2015, Atlantic City, NJ, USA.Description of WorkshopOver a decade ago, Stanford statistician David Donoho predicted that the 21st century will be the century of data. "We can say with complete confidence that in the coming century, high-dimensional data analysis will
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4:00 AM | PCA demo with Fovea

Today's post is guest-contributed by my Google Summer of Code student,
Alex Kuefler. He has been busy developing Fovea, the new tool for
interactively investigating and analyzing complex data and models, and
has a demo in the context of data dimensionality reduction to show off
some new features and possibilities. It also acts as a first tutorial in how
you can set up your own Fovea-based project, about which there will be more.
Table of Contents
Introduction
Setting Up Fovea
Exploratory
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### June 28, 2015

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9:59 PM | GAMS limits on labels

In GAMS strings are used for indexing. E.g. There is a very tight limit on the length of these labels: 63 characters!! This sounds like a strange limit, and it surely is. It is also way too small to handle many datasets from sources like databases and spreadsheets. As these labels are really data, and come form different data sources we do not always have control over the format. That means sometimes we cannot read data. In those cases we have to spend time and effort to devise workarounds.
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9:51 PM | Delft

I arrived a day early in the Netherlands for Computational Geometry Week, to allow me longer to get used to the nine-hour time change. One of the things I did with the extra time was to visit Delft, one of many pretty Dutch canal cities, which turned out to be holding a fun flea market that day. I didn't take any photos of that, but I did get some from a tour of the Royal Delft Museum and Factory there. Royal Delft is probably best known for its ornamental blue-and-white painted plates, but I […]

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8:34 PM | On the teaching blog

More on appropriate and inappropriate use of formal language in math lessons,Eureka Math Tips for Parents -- well, that clears up everything

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Each week, we would like to invite readers of Stats Chat to submit nominations for our Stat of the Week competition and be in with the chance to win an iTunes voucher. Here’s how it works: Anyone may add a comment on this post to nominate their Stat of the Week candidate before midday Friday […]

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If you’d like to comment on or debate any of this week’s Stat of the Week nominations, please do so below!

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7:57 PM | Grandfather turns 90

Congratulations to my Grandfather, Bill Baggaley, who turns 90 this week. We had a wonderful meal earlier today to celebrate the event! Here he is before the wine started flowing ;-).

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5:28 PM | The name we give to bright ideas

From The Book of Strange New Things: … I said that if science could come up with something like the Jump it could surely solve a problem like that. Severin seized hold of that word, “science.” Science, he said, is not some mysterious larger-than-life force, it’s just the name we give to bright ideas that […]

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3:30 PM | What’s So Fun About Fake Data?

Our first Daily Beast column is here.
The post What’s So Fun About Fake Data? appeared first on Statistical Modeling, Causal Inference, and Social Science.

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Nathan Lemoine writes: I’m an ecologist, and I typically work with small sample sizes from field experiments, which have highly variable data. I analyze almost all of my data now using hierarchical models, but I’ve been wondering about my interpretation of the posterior distributions. I’ve read your blog, several of your papers (Gelman and Weakliem, […]
The post Interpreting posterior probabilities in the context of weakly informative priors appeared first on Statistical Modeling,
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### June 27, 2015

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11:57 PM | The rJava Nightmare

I like R. I like Java. I hate the rJava package, or more precisely I hate installing or updating it. Something (often multiple somethings) always goes wrong. I forget that for some reason I need to invoke root privileges when installing it. It needs a C++ library that I could swear I have, except I don't have the developer version of that library installed. Whatever. See this post from 2011 for a previous misadventure.Today's battle was fought after a "successful" installation on my laptop. The […]

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10:33 PM | Report from Geometry Week

I just returned from visiting Eindhoven, the Netherlands, for Computational Geometry Week, including the 31st International Symposium on Computational Geometry, the 4th Annual Minisymposium on Computational Topology, the Workshop on Geometric Networks, the Workshop on Stochastic Geometry and Random Generation, the Workshop on Geometric Intersection Graphs, the Young Researchers Forum, and the CG Week Multimedia Exposition, almost all of which I attended pieces of (it was not possible to attend […]

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Reference: Griffiths, David J. (2005), Introduction to Quantum Mechanics, 2nd Edition; Pearson Education – Problem 1.18. The de Broglie wavelength of a particle, which is the wavelength of an idealized ‘free particle’ which has a precise momentum and thus a completely indeterminate position, is In general, quantum mechanics is needed to describe systems in which […]

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3:16 PM | Greenland Ice Sheet Trivia

I was reading an article today that says that geophysicists have figured out why the Greenland has been experiencing a flurry of magnitude 5 earthquakes. The scientists claim that the earthquakes are being caused by massive icebergs calving off the Greenland ice sheet in a manner that momentarily jams the movement of the ice sheet. The ice sheet and the calved iceberg are so massive that their interaction cause an earthquake.
While the earthquake information was interesting, there was a side […]

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Readers! Dear readers! Today is such a wonderful day for lovers everywhere. We are celebrating love in all its forms. As part of the that celebration, Aunt Pythia has decided to knit up something appropriate: Many apologies for missing last week’s column! Aunt Pythia was busy getting stung by mosquitos and dripped on by a soggy […]

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Eric Tassone writes: So, here’s a Bill James profile from late-ish 2014 that I’d missed until now. It’s baseball focused, which was nice — so many recent articles about him are non-baseball stuff. Here’s an extended excerpt of a part I found refreshing, though it’s probably just that my expectations have gotten pretty low of […]
The post “Faith means belief in something concerning which doubt is theoretically possible.” — William James (again)
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1:03 PM | Nous sommes tous des faussaires

« Comme pour n’importe quel tableau, chaque faux suppose une recherche. Un peintre, qu’il soit faussaire ou non, est, toute sa vie, un étudiant qui se met à l’école de l’art. Je n’ai pas fait un seul Matisse ou un seul Renoir, je les ai faits en dix exemplaires, jusqu’à ce que je comprenne leur […]

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11:43 AM | Uncertainty principle: an example

Reference: Griffiths, David J. (2005), Introduction to Quantum Mechanics, 2nd Edition; Pearson Education – Problem 1.17. Here’s another example of calculating the uncertainty principle. We have a wave function defined as The constant is determined by normalization in the usual way: The expectation value of is from the symmetry of the wave function. The expectation […]