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Posts

August 30, 2015

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9:55 PM | Graph of the day
Literally, this time. I got this from Andrew Gelman, but it’s too good not to share. It’s originally from the Wall Street Journal Apart from the attempts to make the body part representative of the activity, the unwisdom of playing soccer in high heels, and the mystery of what it actually is that she’s eating […]
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8:33 PM | Better Qs
Last week, Sam Shah tweeted this:I immediately replied because I was at Rachel's session, and at Dylan Kane's session and at Robert Kaplinski's session, all of which were on questioning. My #1TMCThing was:(I'm going to let go the fact that I can't seem to get those two tweets to be the same size, but know that it is really annoying me.)What were Sam and Rachel planning, you ask? A most awesome collaborative blog found here. There are already a number of posts, so check it out!Why did I agree to […]
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8:00 PM | Stat of the Week Competition: August 29 – September 4 2015
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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8:00 PM | Stat of the Week Competition Discussion: August 29 – September 4 2015
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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4:48 PM | Apparent motion of a binary star: computer model
Reference: Carroll, Bradley W. & Ostlie, Dale A. (2007), An Introduction to Modern Astrophysics, 2nd Edition; Pearson Education – Chapter 7, Problem 7.16. The TwoStars program included in Carroll & Ostlie’s Appendix K also produces the positions of the two components of a binary star system as seen by an observer on Earth, that is, […]
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3:58 PM | Homology for Normal Humans My friend asked me for help...
Homology for Normal Humans My friend asked me for help understanding this information-theory paper. Specifically, what is homology? I’ll walk you through the graded-chain-complex of a 3-simplex = triangular pyramid, but know that you could extend this kinda easily by sticking simplices together—that’s a “simplicial complex”. You could also stick
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1:25 PM | “Another bad chart for you to criticize”
Stuart Buck sends in this Onion-worthy delight: The post “Another bad chart for you to criticize” appeared first on Statistical Modeling, Causal Inference, and Social Science.
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9:13 AM | Briefly
Three posts about algorithmic transparency and discrimination, via mathbabe.org: in order not to discriminate on, say, race, you need to explicitly use race in your algorithm selection: Cynthia Dwork, at NYT How Big Data is Unfair, by Moritz Hardt Fairness, Accountability, and Transparency, by Hanna Wallach “If you get the software a little bit wrong, […]
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7:39 AM | Radial velocities of a binary system: computer model
Reference: Carroll, Bradley W. & Ostlie, Dale A. (2007), An Introduction to Modern Astrophysics, 2nd Edition; Pearson Education – Chapter 7, Problem 7.15. In their Appendix K, Carroll & Ostlie describe a computer program called TwoStars, which computes radial velocities and magnitudes for an eclipsing binary system. We won’t repeat the description here; rather we’ll […]
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7:26 AM | The Inverse Cube Force Law
Here you see three planets. The blue planet is orbiting the Sun in a realistic way: it’s going around an ellipse. The other two are moving in and out just like the blue planet, so they all stay on the same circle. But they’re moving around this circle at different rates! The green planet is […]
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6:57 AM | Genetically targeted cancer treatment
Targeting cancer treatments to specific genetic variants has certainly had successes with common mutations — the most well known example must be Herceptin for an important subset of  breast cancer.  Reasonably affordable genetic sequencing has the potential for finding specific, uncommon mutations in cancers where there isn’t a standard, approved drug. Most good ideas in medicine don’t […]

August 29, 2015

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7:26 PM | New CEA Overview of GDO
The U.S. Council of Economic Advisors has a nice new review of "Gross Domestic Output" (GDO), a simple average of expenditure- and income-side GDP estimates now published by the BEA.In an earlier post I wrote rather negatively about GDO as compared to GDPplus, which is an optimally-weighted blend rather than a simple average. (See the FRB Philadelphia GDPplus site and the corresponding Aruba et al. paper available there.) My view has not changed.But I want to be very clear […]
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7:06 PM | About the central multinomial coefficient
We have already listed many basic aspects of the multinomial law in a former post. This post is devoted to an additional remark. Recall that the multinomial law \[ \mathcal{M}(n,p_1\delta_{e_1}+\cdots+p_d\delta_{e_d}) \] where \( {e_1,\ldots,e_d} \) is the canonical basis of \( {\mathbb{R}^d} \) is given by \[ (p_1\delta_{e_1}+\cdots+p_d\delta_{e_d})^{*n} =\sum_{\substack{(n_1,\ldots,n_d)\in\mathbb{N}^d\\n_1+\cdots+n_d=n}} \binom{n}{n_1,\ldots,n_d}p_1^{n_1}\cdots […]
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1:54 PM | Performing design calculations (type M and type S errors) on a routine basis?
Somebody writes writes: I am conducting a survival analysis (median follow up ~10 years) of subjects who enrolled on a prospective, non-randomized clinical trial for newly diagnosed multiple myeloma. The data were originally collected for research purposes and specifically to determine PFS and OS of the investigational regimen versus historic controls. The trial has been […] The post Performing design calculations (type M and type S errors) on a routine basis? appeared first on […]
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1:34 PM | Aunt Pythia’s advice
Readers, did you know Aunt Pythia is a rabid biker? And did you know that the High Bridge just opened for the first time in 40 years? Aunt Pythia is itching to bike all over it as soon as she’s shot this Saturday’s wisdom wad all over your browser. Fun facts about the High Bridge: It’s […]
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8:45 AM | Net Reclassification Index: surprisingly weird.
Attention Conservation Notice: Long. Really long. No, longer than that. Here: read the original instead.The Net Reclassification Index (NRI) is a summary of improvement in prediction when new information is added, and an intuitively plausible one. Suppose that we’re trying to predict $Y=1$ vs $Y=0$, and that for person $i$ we have an old predicted probability $\hat p_{\textrm{old}}(i)$ and a new predicted probability $\hat p_{\textrm{new}}(i)$.  We’d hope that the probabilities for cases […]

August 28, 2015

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5:00 PM | PolyBowls – From zero to OpenSCAD in 6 minutes
The following collection of bowls and pen holders we are all generated from the same simple OpenSCAD code: Customizable PolyBowl on Thingiverse: http://www.thingiverse.com/thing:988598 This is a really simple design whose main purpose is to serve as an accessible introduction to designing with… Continue reading →
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4:51 PM | Machine Learning and Homomorphic Encryption - implementation -
We have mentioned homomorphic encryption here on Nuit Blanche mostly because of Andrew McGregor et al's work on the subject (see references below). Today, we have a Machine Learning approach using this encoding strategy, which in effect is not really that far from the idea of homomorphic sketches  or random projections for low dimensional manifolds. Without further ado:A review of homomorphic encryption and software tools for encrypted statistical machine learning by  Louis J. M. […]
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3:57 PM | [일상] 성북동/팔각정공원 – 북악 스카이웨이 심야 드라이브
  오늘(150828 金) 새벽 5시즘에 기분이 꿀꿀하다는 이유로 또 집 뒷산에 있는 팔각정 공원에 올랐다. 그간 주차장에서 먼지만 쌓이고 있었던 붕붕이 요즘 정말 많이 굴리는듯..     도착했더니 해가 슬금슬금 뜨고 있다. 하늘 색은 보정한 것이 아니고 실제로 그라데이션 넣은것처럼 … Continue reading →Related Posts ?2015년 8월 24일의 일상 – 홍대/엘루이스/북악 […]
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3:37 PM | A Generative Modeling Challenge
So, I've been discussing declarative vs generative models. Here's a case where I think the declarative model makes good sense, how would you model this? y is a vector of 1000 timeseries samples from some audio system. On one end is a highly sensitive microphone that puts out a voltage signal proportional to the instantaneous […]
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1:04 PM | New paper on psychology replication
The Open Science Collaboration, a team led by psychology researcher Brian Nosek, organized the replication of 100 published psychology experiments. They report: A large portion of replications produced weaker evidence for the original findings despite using materials provided by the original authors, review in advance for methodological fidelity, and high statistical power to detect the […] The post New paper on psychology replication appeared first on Statistical Modeling, Causal […]
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1:00 PM | The third reason Trump is so interesting
I think we've covered 1. and 2.:1. Trump has brought a gun to a knife fight and has no intention of politely turning it in at the door. The threat of a third party run on an anti-immigrant ticket gives him exceptional leverage.2. Trump is willing to take extreme positions that appeal to the base and present them in unvarnished terms even when they are repugnant to the general population;But we haven't said much about  this:3. Trump is also just as willing to abandon conservative sacred […]
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12:46 PM | A huge win for contractors and franchise workers
Today I’m celebrating some good news for working-class people in this country. Namely, the definition of “employee” is changing, making it easier for employees at McDonalds and other places to complain about poor treatment. The good news comes via a National Labor Relations Board ruling yesterday. I wrote previously about the economics of McDonalds franchises, but […]
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5:00 AM | Mash: Fast genome distance estimation using the MinHash algorithm - implementation -
In this Sunday Morning Insight: What Happens When You Cross into P Territory ?, I mentioned this article on using LSH for genome alignment from long read technology (PacBio RS II or Oxford Nanopore MiNion).Assembling Large Genomes with Single-Molecule Sequencing and Locality Sensitive Hashing by Konstantin Berlin, Sergey Koren, Chen-Shan Chin, James Drake, Jane M Landolin, Adam M Phillippywhile assembling the genome is important, with cheap and fast long reads, the goalpost is now slowly moving […]
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2:13 AM | Bayesian inference in a nut...bag
Suppose you are in a Kindergarten class, and you have a bag containing 100 mixed nuts, Brazil, Walnut, Almond, Hazelnut, etc. Now one of the children reaches in, pulls out a nut, and tells you what kind it is. How much does it weigh? Let's make the assumption that the nuts remaining are not radically […]
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12:00 AM | Natural language processing of new jokes from 2015
This is a brief update to a previous post: “Python, natural language processing and predicting funny”. In that post I carried out some basic natural language processing with Python to predict whether or not a joke is funny. In this post I just update that with some more data from this year’s Edinburgh Fringe festival. Take a look at the ipython notebook which shows graphics and outputs of all the jokes. Interestingly this year’s winning joke is not deemed funny by the basic model […]

August 27, 2015

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10:08 PM | Trying again
This graph is from the Open Science Framework attempt to replicate 100 interesting results in experimental psychology, led by Brian Nozek and published in Science today. About a third of the experiments got statistically significant results in the same direction as the originals.  Averaging all the experiments together,  the effect size was only half that […]
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3:35 PM | Nonlinear functions on the left hand side and all that jazz
In my posts about assigning distributions to functions of data and parameters, I mentioned the tried and true example of trying to apply a distribution to a nonlinear function of a parameter: log(foo) ~ normal(0,1); In Stan at least, this does NOT imply that samples of foo have a lognormal frequency distribution, for that you […]
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3:31 PM | 2015년 8월 24일의 일상 – 홍대/엘루이스/북악 팔각정공원
요즘들어 휴일 전날 항상 즐기는 심야 드라이브~ 이 날은 홍대 쪽으로 좀 가 봤다. 심야에 차타고 홍대 가니까 의외로 금방이다. 체감상 10~15분 정도밖에 안 걸린듯? 일요일 밤이라 그런지 사람들도 별로 없고..     출출해서 버거킹에서 주니어 와퍼세트 섭취. 버거킹이 패스트푸드 … Continue reading →Related Posts ?2015년 3월 20일의 일상 – 창경궁 / 인사동 탐방2015년 […]
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3:30 PM | Toward a unified theory of sparse dimensionality reduction in Euclidean space
 So we are now converging toward a theory for using sparse random projections for a variety of problems. Toward a unified theory of sparse dimensionality reduction in Euclidean space  by Jean Bourgain, Sjoerd Dirksen, Jelani Nelson Let Φ∈Rm×n be a sparse Johnson-Lindenstrauss transform [KN14] with s non-zeroes per column. For a subset T of the unit sphere, ε∈(0,1/2) given, we study settings for m,s required to ensure EΦsupx∈T∣∣∥Φx∥22−1∣∣<ε,i.e. so […]
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