Posts

October 24, 2014

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10:33 AM | The class warfare of Halloween
What’s the best thing about Halloween, the dress-up or the candy? Or is it the fact that, for that one night, you can go up to people’s houses and ring their bell and talk to them when they answer the door, and if you’re a kid you can even get demand and receive a gift? […]
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10:01 AM | L'Italia che vince!
E' un periodo che, per vari motivi, mi perdo informazioni. Per fortuna ci sono e-mail e newsletter che informano, e così accade anche per i risultati della spedizione italiana alle Olimpiadi Internazionali dell'Astronomia che dal Kirghizistan, sede della competizione, tornano con tre medaglie, un oro e due bronzi, festeggiati persino da Samantha Cristoforetti su twitter. Veniamo, però, al comunicato stampa inviatomi da Stefano Sandrelli:Sono tre, i premi vinti quest'anno dalla […]
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3:42 AM | Is the two-Burke ballot the new butterfly ballot?
Scott Walker’s opponent takes on the WEDC: BURKE:  One other area outside of that that people really should take a look at is the Wisconsin Economic Development Corporation, which was a nonprofit, public-private corporation created in 2011 which Governor Walker used to make himself the chair of. What’s most interesting is that Governor Walker’s experience […]

October 23, 2014

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10:14 PM | Feller’s shoes and Rasmus’ socks [well, Karl's actually...]
Yesterday, Rasmus Bååth [of puppies' fame!] posted a very nice blog using ABC to derive the posterior distribution of the total number of socks in the laundry when only pulling out orphan socks and no pair at all in the first eleven draws. Maybe not the most pressing issue for Bayesian inference in the era […]
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9:08 PM | No, Michael Jordan didn’t say that!
The names are changed, but the song remains the same. First verse. There’s an article by a journalist, The odds, continually updated, by F.D. Flam in the NY Times to which Andrew responded in blog form, No, I didn’t say that, by Andrew Gelman, on this blog. Second verse. There’s an article by a journalist, […] The post No, Michael Jordan didn’t say that! appeared first on Statistical Modeling, Causal Inference, and Social Science.
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2:43 PM | Free Fibonacci Sequences
John Conway likes playing with the Fibonacci sequence. He invented many new sequences using the following trick. The next number in the sequence is the sum of the two previous number adjusted in some way. Free Fibonacci sequences were invented this way. Here is the recurrence for an n-free Fibonacci sequence: the next number in […]
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1:07 PM | Some questions from our Ph.D. statistics qualifying exam
In the in-class applied statistics qualifying exam, students had 4 hours to do 6 problems. Here were the 3 problems I submitted: In the helicopter activity, pairs of students design paper ”helicopters” and compete to create the copter that takes longest to reach the ground when dropped from a fixed height. The two parameters of the […] The post Some questions from our Ph.D. statistics qualifying exam appeared first on Statistical Modeling, Causal Inference, and Social […]
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12:42 PM | A Case for Anonymous Open Review
I recently reviewed a manuscript for the pioneering journal PeerJ. This presented me with a quandary. PeerJ’s experiment in open reviewing is nicely outlined in their recent post, and includes two steps: reviewers can sign their reports, and authors can publish the review history alongside their accepted paper. My quandary was this: I love the second idea, and think it is an important step forward in opening up the peer review process; but I don’t like to sign my reviews.... Read […]
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10:45 AM | Links (with annotation)
I’ve been heads down writing this week but I wanted to share a bunch of great stuff coming out. Here’s a great interview with machine learning expert Michael Jordan on various things including the big data bubble (hat tip Alan Fekete). I had a similar opinion over a year ago on that topic. Update: here’s […]
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7:02 AM | 'Mitoflashes' indicate acidity changes rather than free radical bursts
As we've written about before, mitochondria generate the energy required by our cells through respiration that involves using an "electrochemical gradient" as an energy store (a bit like pumping water up into a reservoir for energy storage to then harness it flowing down the gradient of a hill to turn a turbine), and produces superoxide (free oxygen radicals) as a by-product (a bit like sparks when the pumps are running hot). The fundamental importance of this machinery which not only delivers […]
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6:14 AM | BibTool on the air
Yesterday night, I realised I had about 30 versions of my “mother of all .bib” bib file, spread over directories and with broken links with the original mother file… (I mean, I always create bib files in new directories by a hard link, ln ~/mother.bib but they eventually end up with a life of their […]
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1:14 AM | Francis Galton could be kind of a jerk
As here (from Hereditary Genius, p. 21) Every tutor knows how difficult it is to drive abstract conceptions, even of the simplest kind, into the brains of most people—how feeble and hesitating is their mental grasp—how easily their brains are mazed—how incapable they are of precision and soundness of knowledge. It often occurs to persons familiar with […]

October 22, 2014

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7:59 PM | Stan 2.5, now with MATLAB, Julia, and ODEs
As usual, you can find everything on the Stan Home Page. Drop us a line on the stan-users group if you have problems with installs or questions about Stan or coding particular models. New Interfaces We’d like to welcome two new interfaces: MatlabStan by Brian Lau, and  Stan.jl (for Julia) by Rob Goedman. The new […] The post Stan 2.5, now with MATLAB, Julia, and ODEs appeared first on Statistical Modeling, Causal Inference, and Social Science.
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4:27 PM | Stuck at 225
My weight loss progress is progress no more. I am stuck at 225. I have my morning routine. I wake up and jog to the facilities; then I weigh myself. Why do I do this in this order? Because I do not use an alarm-clock. I depend on my own hydro-alarm that wakes me up […]
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2:29 PM | Where Do Probability Measures Come From?
Tom Avery explains a categorical construction of the concept of probability measure.
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2:29 PM | Martin Gardner
Come ha ricordato Maurizio Codogno è stato il centenario di Martin Gardner. Recupero oggi con la traduzione di un articolo di David Singmaster uscito su "Nature" nel 2010 come ricordo per la figura di riferimento che ha rappresentato per moltissimi lettori, amanti della matematica e matematici professionisti.Dalla metà degli anni '50 fino ai primi anni '80 del XX sexolo, probabilmente la più nota sezione di Scientific American è stata Mathematical games di Martin […]

Singmaster D. (2010). Obituary: Martin Gardner (1914–2010), Nature, 465 (7300) 884-884. DOI: http://dx.doi.org/10.1038/465884a

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2:29 PM | Controversial App
Just a couple of minutes ago I was watching this video: This video presents an application (PhotoMath) that acts as a smart camera calculator or problem solver. It reads and solves mathematical expressions by using the camera of your mobile device … Continue reading →
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1:56 PM | Sailing between the Scylla of hyping of sexy research and the Charybdis of reflexive skepticism
Recently I had a disagreement with Larry Bartels which I think is worth sharing with you. Larry and I took opposite positions on the hot topic of science criticism. To put things in a positive way, Larry was writing about some interesting recent research which I then constructively criticized. To be more negative, Larry was […] The post Sailing between the Scylla of hyping of sexy research and the Charybdis of reflexive skepticism appeared first on Statistical Modeling, Causal Inference, […]
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8:47 AM | Integration trick
Here’s a clever example from Paul Nahin’s new book Inside Interesting Integrals. Suppose you want to evaluate Since the range of integration is symmetric around zero, you might think to see whether the integrand is an odd function, in which case the integral would be zero. (More on such symmetry tricks here.) Unfortunately, the integrand […]

October 21, 2014

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11:11 PM | Celebrate Mathematicians part 3
We are on 20th October and just a little over half of the mathematicians of the month are covered. Impressive the fact that in the last 11 days we are celebrating 21 mathematicians, while in 20 days we have only … Continue reading →
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10:14 PM | delayed acceptance [alternative]
In a comment on our Accelerating Metropolis-Hastings algorithms: Delayed acceptance with prefetching paper, Philip commented that he had experimented with an alternative splitting technique retaining the right stationary measure: the idea behind his alternative acceleration is again (a) to divide the target into bits and (b) run the acceptance step by parts, towards a major reduction […]
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10:13 PM | Simulating a bet on a whole series from bets on individual games
From Mind Your Decisions, a puzzle about gambling: Your friend wants to make an even-payoff bet on the outcome of the entire World Series. That is, he wants to make a $100 bet so that if his team is the champion he will win $100, and if his team loses he will lose all of […]
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5:31 PM | News Round-up, 21/10/14
Here’s some quick stories from the world of maths this week. Samuel Hansen’s Relatively Prime Kickstarter has been funded You may have noticed us banging on about this, but Aperiodical editor Peter Rowlett’s former podcasting partner in crime, Samuel Hansen, is up to his usual tricks, crowdfunding an excellent series of podcasts telling stories about... Read more »
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3:36 PM | Inflazione infinita e fine del tempo
Come saprete i dati di BICEP che sembrava dovessero confermare l'inflazione cosmica e le onde gravitazionali primordiali hanno subito una verifica negativa. Come spiegano molto bene Amedeo e Sandro, l'interpretazione dei risultati è stata completamente ribaltata dalle analisi di Planck.Uno degli aspetti che, con quell'annuncio di metà aprile, non avevo trattato ma che mi sarebbe piaciuto era la questione dell'inflazione infinita. Questa ipotesi teorica venne introdotta da Alan […]

Alan H. Guth (2001). Eternal Inflation, arXiv: http://arxiv.org/abs/astro-ph/0101507v1

Guth A.H. (2007). Eternal inflation and its implications, Journal of Physics A: Mathematical and Theoretical, 40 (25) 6811-6826. DOI: 10.1088/1751-8113/40/25/S25

Bousso R., Freivogel B., Leichenauer S. & Rosenhaus V. (2011). Eternal inflation predicts that time will end, Physical Review D, 83 (2) DOI: http://dx.doi.org/10.1103/physrevd.83.023525

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2:37 PM | Little things matter – for want of a semicolon.
The Prof is back. A couple of years back Professor Christopher M. Graney, known to his friends as Chris, wrote a highly informative guest post for The Renaissance Mathematicus defending the honour of Tyco Brahe against his ignorant modern critics. In the mean time … Continue reading →
Editor's Pick
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1:59 PM | introducing Badger Bracketology, a tool for forecasting the NCAA football playoff
Today I am introducing Badger Bracketology: http://bracketology.engr.wisc.edu/ I have long been interested in football analytics, and I enjoy crunching numbers while watching the games. This year is the first season for the NCAA football playoff, where four teams will play to determine the National Champion. It’s a small bracket, but it’s a start in the right direction. […]
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1:18 PM | Try a spaghetti plot
Joe Simmons writes: I asked MTurk NFL fans to consider an NFL game in which the favorite was expected to beat the underdog by 7 points in a full-length game. I elicited their beliefs about sample size in a few different ways (materials .pdf; data .xls). Some were asked to give the probability that the better […] The post Try a spaghetti plot appeared first on Statistical Modeling, Causal Inference, and Social Science.
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1:10 PM | Questions and answers from Cal Poly
On a recent visit to California Polytechnic State University, I met a lot of great folks and was asked several good questions about teaching and learning. Here are some of my answers.
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11:05 AM | Guest post: The dangers of evidence-based sentencing
This is a guest post by Luis Daniel, a research fellow at The GovLab at NYU where he works on issues dealing with tech and policy. He tweets @luisdaniel12. Crossposted at the GovLab. What is Evidence-based Sentencing? For several decades, parole and probation departments have been using research-backed assessments to determine the best supervision and treatment […]

October 20, 2014

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10:14 PM | control functionals for Monte Carlo integration
This new arXival by Chris Oates, Mark Girolami, and Nicolas Chopin (warning: all colleagues & friends of mine!) is a variation on control variates, but with a surprising twist namely that the inclusion of a control variate functional may produce a sub-root-n (i.e., faster than √n) convergence rate in the resulting estimator. Surprising as I […]
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