# Posts

### November 23, 2014

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How would you create a table of trig functions without calculators or calculus? It’s not too hard to create a table of sines at multiples of 3°. You can use the sum-angle formula for sines sin(α+β) = sin α cos β + sin β cos α. to bootstrap your way from known values to other […]

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. . . and Kaiser Fung is unhappy. In a post entitled, “Princeton’s loss of nerve,” Kaiser writes: This development is highly regrettable, and a failure of leadership. (The new policy leaves it to individual departments to do whatever they want.) The recent Alumni publication has two articles about this topic, one penned by President […]
The post Princeton Abandons Grade Deflation Plan . . . appeared first on Statistical Modeling, Causal Inference, and Social Science.

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2:00 PM | The Math Geek Holiday Gift Guide

Looking for a gift that says, “Hey, I know you like math”? Look no further. There is an embarrassment of riches when it comes to wonderful mathematical things to give to people, but here are some of...
-- Read more on ScientificAmerican.com

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1:16 PM | Christmas Presents for Herrrr…

I believe that after my last post about ideas for Christmas gifts, you would expect this post immediately. With no further introduction, here are some of my favorite gift ideas for HeRRrrr: 1. Jewelry - I personally always like a good … Continue reading →

### November 22, 2014

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11:14 PM | Challis Lectures

I had a great time during this short visit in the Department of Statistics, University of Florida, Gainesville. First, it was a major honour to be the 2014 recipient of the George H. Challis Award and I considerably enjoyed delivering my lectures on mixtures and on ABC with random forests, And chatting with members […]

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10:41 PM | A temperature puzzle

Last Friday morning (the 14th) it was unseasonably cold in Atlanta. On the way to work I noticed my car’s display giving the following temperature readings: 28, 30, 32, 34, 36 – all in Fahrenheit. It somehow knew to avoid … Continue reading →

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3:12 PM | Ergodic

Roughly speaking, an ergodic system is one that mixes well. You get the same result whether you average its values over time or over space. This morning I ran across the etymology of the word: In the late 1800s, the physicist Ludwig Boltzmann needed a word to express the idea that if you took an […]

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2:53 PM | Blogs > Twitter

Tweeting has its virtues, I’m sure. But over and over I’m seeing these blog vs. twitter battles where the blogger wins. It goes like this: blogger gives tons and tons of evidence, tweeter responds with a content-free dismissal. The most recent example (as of this posting; remember we’re on an approx 2-month delay here; yes, […]
The post Blogs > Twitter appeared first on Statistical Modeling, Causal Inference, and Social Science.

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2:48 PM | Aunt Pythia’s advice

Greetings, friends! I’ve missed you all! Since returning from her travels, Aunt Pythia has been continuously marveling in the wonders of flannel and wool, and has decided to knit up something along these Celtic lines: Here’s the thing, though: the pattern comes from the excellent book Celtic Charted Designs that Aunt Pythia is absolutely sure she has […]

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1:31 PM | The globe of Galileo

video by @ulaulaman #levitation Published by Gianluigi (@ulaulaman) in data: Nov 11, 2014 at 4:41 PSTIt's just a little Earth, turns and levitates above its base, reminding those who contributed to give it its rightful place in space. The globe can light up using the switch on the base. It works in the current network.

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1:43 AM | 50 shades of gray goes pie-chart

Rogier Kievit sends in this under the heading, “Worst graph of the year . . . horribly unclear . . . Even the report doesn’t have a legend!”: My reply: It’s horrible but I still think the black-and-white Stroop test remains the worst visual display of all time: What’s particularly amusing about the Stroop image […]
The post 50 shades of gray goes pie-chart appeared first on Statistical Modeling, Causal Inference, and Social Science.

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12:57 AM | A general parity problem obstruction

Many problems and results in analytic prime number theory can be formulated in the following general form: given a collection of (affine-)linear forms , none of which is a multiple of any other, find a number such that a certain property of the linear forms are true. For instance: For the twin prime conjecture, one […]

### November 21, 2014

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11:14 PM | a pile of new books

I took the opportunity of my weekend trip to Gainesville to order a pile of books on amazon, thanks to my amazon associate account (and hence thanks to all Og’s readers doubling as amazon customers!). The picture above is missing two Rivers of London volumes by Ben Aaraonovitch that I already read and left at […]

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Part of my job is to help students figure out if grad school is for them. Over the years, I’ve accumulated a few great resources for students thinking about a PhD. Here are some of my favorites. Here is a link to the first of a series of ten blog posts by Jean Yang, who decided to leave […]

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2:50 PM | Incredible Floor ^_^

The internet is a great way to find incredible things if you want to look for them. Just yesterday I was looking for inspiration and ideas and I found this: A huge video game shop in Paris (Fnac at La Defense). … Continue reading →

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Well put, Rob Weiss. This is not to say that one must always use an informative prior; oftentimes it can make sense to throw away some information for reasons of convenience. But it’s good to remember that, if you do use a noninformative prior, that you’re doing less than you could.
The post “If you’re not using a proper, informative prior, you’re leaving money on the table.” appeared first on Statistical Modeling, Causal Inference, and Social Science.

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1:18 PM | some LaTeX tricks

Here are a few LaTeX tricks I learned or rediscovered when working on several papers the past week: I am always forgetting how to make aligned equations with a single equation number, so I found this solution on the TeX forum of stackexchange, Namely use the equation environment and then an aligned environment inside. Or […]

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This is a guest post by FogOfWar. The phrase is used constantly by politicians and economists, but what does it actually mean to “create jobs”? Here’s an example: I open a coffee shop and hire two people. So I’ve created three jobs (counting myself), right? Really? Let’s assume for the moment that I’m no more […]

### November 20, 2014

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On December 10, I will alas not travel to London to attend the Read Paper on sequential quasi-Monte Carlo presented by Mathieu Gerber and Nicolas Chopin to The Society, as I fly instead to Montréal for the NIPS workshops… I am quite sorry to miss this event, as this is a major paper which brings […]

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9:54 PM | Soil Scientists Seeking Super Model

I (Bob) spent last weekend at Biosphere 2, collaborating with soil carbon biogeochemists on a “super model.” Model combination and expansion The biogeochemists (three sciences in one!) have developed hundreds of competing models and the goal of the workshop was to kick off some projects on putting some of them together intos wholes that are […]
The post Soil Scientists Seeking Super Model appeared first on Statistical Modeling, Causal Inference, and Social Science.

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7:20 PM | limbo IPA

Filed under: pictures, Travel, Wines Tagged: ÌPA, beer, Limbo IPA, Long Trail Brewing Company, Maine, microbrewery, USA, Vermont

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6:23 PM | The Geometry of Restricted Partitions

Last week, I attended the IMA Workshop on Geometric and Enumerative Combinatorics which was, hands down, the best conference I have ever attended. The speaker lineup was simply amazing and I return brimming with ideas for future projects and collaborations. I felt, therefore, particularly honored to be invited to speak in front of this audience, given that so many of my personal “academic heroes”, who I have cited so often, were present.
Given these high stakes, I am delighted to
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3:13 PM | La pila

Le lampade portatili prendono nome dalle "pile" che forniscono loro energia, e sono poi le stesse dei giocattoli, delle radioline, dei minicalcolatori. Quei cilindretti pieni di strane sostanze schifosette che quando escono sporcano tutto hanno un antenato illustre: vennero inventati da Volta, nei primi anni del 1800, quando scoperse che sovrapponendo una "pila" di dischi di rame e zinco alternati a panno intinto in acqua e acido solforico si produceva una lieve
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2:40 PM | Retrospective clinical trials?

Kelvin Leshabari writes: I am a young medical doctor in Africa who wondered if it is possible to have a retrospective designed randomised clinical trial and yet be sound valid in statistical sense. This is because to the best of my knowledge, the assumptions underlying RCT methodology include that data is obtained in a prospective […]
The post Retrospective clinical trials? appeared first on Statistical Modeling, Causal Inference, and Social Science.

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12:01 PM | I am old in Haiti

I am old in Haiti. This fact dawns on me slowly over the six days I am there, because there is so much to take in. Mostly I figure it out because I am constantly amazed by how beautiful and healthy everyone looks. But then again, I keep finding myself thinking, people who are 24 […]

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4:15 AM | On proof and progress in feminism

The recent allegations against several celebrities have led to a broader conversation on how we, as a society, don’t believe women. In a “he said, she said” situation, we trust the man and assume that the woman is either mistaken … Continue reading →

### November 19, 2014

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11:36 PM | ANU hiring postdocs

Amnon Neeman has just put up an ad for two postdoctoral positions at the ANU. He says: “The successful applicants should have strong research interests and activities in or related to one of the following fields: Algebraic Geometry, Commutative Algebra, Representation Theory, Algebraic Topology, Algebraic K-Theory. Skills at applying the techniques of triangulated categories to […]

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11:14 PM | Bayesian evidence and model selection

Another arXived paper with a topic close to my interests, posted by Knuth et al. today. Namely, Bayesian model selection. However, after reading the paper in Gainesville, I am rather uncertain about its prospects, besides providing an entry to the issue (for physicists?). Indeed, the description of (Bayesian) evidence is concentrating on rough approximations, in […]

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8:57 PM | Making screencasts: The working example

In this third video of three on making screencasts, we discuss the "working example" video where the instructor is writing out longhand on a screen as you would at a whiteboard.

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4:37 PM | No Averages Solution

I recently posted the following old Olympiad problem: Prove that you can choose 2k numbers from the set {1, 2, 3, …, 3k−1} in such a way that the chosen set contains no averages of any two of its elements. Let me show how to find 2k − 1 such numbers. We can pick all […]