# Posts

### March 03, 2015

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Nineteen Eighty — if I had to pick the year that computational modeling invaded evolutionary game theory then that would be it. In March, 1980 — exactly thirty-five years ago — was when Robert Axelrod, a professor of political science at University of Michigan, published the results of his first tournament for iterated prisoner’s dilemma […]

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I finished building a cabinet a couple of months ago just as the extreme cold arrived, which made my garage shop uninhabitable.. The ten-day forecast is now showing rising temperatures, so I am starting to think about my next cabinet construction effort. Continue reading →

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3:56 AM | Hadamard on iteration

Many of heard of Hadamard only through his book “Psychology of Invention in the Mathematical Field”, but he was a first rate and prolific mathematician as well as a commentator on how mathematicians work. As is well known, the problem … Continue reading →

### March 02, 2015

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10:30 PM | Introducing shinyStan

As a project for Andrew’s Statistical Communication and Graphics graduate course at Columbia, a few of us (Michael Andreae, Yuanjun Gao, Dongying Song, and I) had the goal of giving RStan’s print and plot functions a makeover. We ended up getting a bit carried away and instead we designed a graphical user interface […]
The post Introducing shinyStan appeared first on Statistical Modeling, Causal Inference, and Social Science.

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For yesterday, the most perceptive comment came from Slugger: Rabbit Angstrom is a perfect example of the life that the Buddha warns against. He is a creature of animal passions who never gains any enlightenment. In any case, I think we can all agree that Buddha is a far more interesting person than Updike. But, […]
The post Rembrandt van Rijn (2) vs. Betrand Russell appeared first on Statistical Modeling, Causal Inference, and Social Science.

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Ben Alamar reflects on the rise of data analytics in the NBA (link). I like this passage very much, which really nails home the point that good analytics requires intuition: The hours of waiting [during draft meetings] were often filled with watching film of prospects. It helped me refine my analysis, as I soaked up details from scouts that I never would have seen on my own. ("Rewind that. ... Did you see his foot placement there, getting ready for the rebound? That's NBA ready.") […]

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6:05 PM | Spacetime diagrams: an example

References: Griffiths, David J. (2007), Introduction to Electrodynamics, 3rd Edition; Pearson Education – Chapter 12, Post 23. As an example of a spacetime diagram, suppose we have our usual two inertial frames with at rest relative to observer and moving at speed in the direction, with the origins of the two systems coinciding as usual. […]

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5:35 PM | Spacelike intervals

References: Griffiths, David J. (2007), Introduction to Electrodynamics, 3rd Edition; Pearson Education – Chapter 12, Post 22. If two events are separated by a spacelike interval, neither event can affect the other, since different observers may disagree about the order of the events. Here are examples of a couple of misconceptions that sometimes arise about […]

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The generalized Lasso with non-linear observations by Yaniv Plan, Roman Vershynin We study the problem of signal estimation from non-linear observations when the signal belongs to a low-dimensional set buried in a high-dimensional space. A rough heuristic often used in practice postulates that non-linear observations may be treated as noisy linear observations, and thus the signal may be estimated using the generalized Lasso. This is appealing because of the abundance of efficient, specialized
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It's Monday and that means counting circle. Today I thought we would work with some negative numbers so we started at -173 and went up by 4. Many were using their fingers or counting up by 1 four times aloud so I opted to stick to a simple counting circle today.We did discuss the pattern in the one's digits after we finished, which some had not noticed. Hopefully that will give them another strategy for next time.While I was away, my class took two days to work on similar triangles. I love that
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I’ve said it before but it’s worth saying again. The conventional view: Hyp testing is all about rejection. The idea is that if you reject the null hyp at the 5% level, you have a win, you have learned that a certain null model is false and science has progressed, either in the glamorous “scientific […]
The post What hypothesis testing is all about. (Hint: It’s not what you think.) appeared first on Statistical Modeling, Causal Inference, and Social Science.

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3:00 PM | Hamming’s Code

Or how to detect and correct errors Last time we made a quick tour through the main theorems of Claude Shannon, which essentially solved the following two problems about communicating over a digital channel. What is the best encoding for information when you are guaranteed that your communication channel is error free? Are there any encoding schemes that can recover […]

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p-values banned!The journal Basic and Applied Social Psychology (BASP) made news recently by "banning" p-values. Here's the editorial that explains why and my summary of their major points:"...the null hypothesis significance testing procedure (NHSTP) is invalid...". "We believe that the p<0.5 bar is too easy to pass and sometimes serves as an excuse for lower quality research.""Confidence intervals suffer from an inverse problem that is not very different from that
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2:00 PM | On deck this week

Mon: Absolute skepticism equals absolute credulity (statistics edition) Rembrandt van Rijn (2) vs. Betrand Russell Tues: One simple trick to make Stan run faster George Carlin (2) vs. Barbara Kruger Wed: I actually think this infographic is ok Bernard-Henry Levy (3) vs. Jacques Derrida Thurs: Defaults, once set, are hard to change. Judy Garland (4) […]
The post On deck this week appeared first on Statistical Modeling, Causal Inference, and Social Science.

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Data Science and Business Analytics are red-hot in the business world -- there are definitely more jobs than there are qualified people. Is this the right field for you? How do you find a job in this field? More importantly, how do you build a lasting career in analytics? I'll be addressing these questions in a new course I'm developing to be held in late March. Here is the tentative outline of the one-day seminar. Please let me know if you have any suggestions. There is still time to change […]

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Today I want to share two articles today which call on the public to try to understand scientific error at a deeper level than we do now. First, an academic journal called Basic and Applied Social Psychology (BASP) has decided to ban articles using p-values. This was written up in Nature news (hat tip Nikki Leger) […]

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After what seems like a long time, we are back on the bad education statistics beat. Joseph kicked things off with this post discussing some recent charter school research, particularly this paper by Angrist et al. I followed by reposting a couple of earlier pieces on attrition.If you didn't see them when they came out, I strongly recommend you take a minute a read those two reposts (Selection effects on steroids and Selection on Spinach*). This is a big, incredibly complex story and it makes […]

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7:00 AM | Silhouettes

Romeo, Juliet, balcony in silhouette, makin o’s with her cigarette, it’s juliet (Flapper Girl, The Lumineers) Two weeks ago I published this post for which designed two different visualizations. At the end, I decided to place words on the map of the United States. The discarded visualization was this other one, where I place the words over the silhouette … Continue reading Silhouettes →

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On the Equivalence between Quadrature Rules and Random Features by Francis Bach We show that kernel-based quadrature rules for computing integrals are a special case of random feature expansions for positive definite kernels for a particular decomposition that always exists for such kernels. We provide a theoretical analysis of the number of required samples for a given approximation error, leading to both upper and lower bounds that are based solely on the eigenvalues of the associated
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3:16 AM | Graphemes

Here’s something amusing I ran across in the glossary of Programming Perl: grapheme A graphene is an allotrope of carbon arranged in a hexagonal crystal lattice one atom thick. Grapheme, or more fully, a grapheme cluster string is a single user-visible character, which in turn may be several characters (codepoints) long. For example … a “ȫ” […]

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I had a deja vu moment this week. Yahoo had an article on how a large amount of manganese nodules have been found on the Atlantic Ocean's seafloor (Figure 1). Back in the 1960s, I remember reading about Howard Hughes building the Glomar Explorer to mine manganese nodules from the bottom of the ocean. It turned out this story was a CIA cover story for Project Azorian, but that is another story. Continue reading →

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I had a deja vu moment this week. Yahoo had an article on how a large amount of manganese nodules have been found on the Atlantic Ocean's seafloor (Figure 1). Back in the 1960s, I remember reading about Howard Hughes building the Glomar Explorer to mine manganese nodules from the bottom of the ocean. It turned out this story was a CIA cover story for Project Azorian, but that is another story. Continue reading →

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2:12 AM | Consonance and Dissonance in Music

Recently I've had a lot of fun composing music using Just Intonation. As a step toward explaining my compositional approach, today I'd like to discuss a theory of why certain combinations of notes sound consonant and others dissonant. This is a controversial subject, since it depends partly on the biology of the ear and brain, and partly on culture. In fact, the list of intervals that are considered consonant or dissonant has sometimes changed over the centuries according to
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1:30 AM | Responsive design for data visualization

Much of the analytic insight that we consume every day goes through the minds and hands of data scientists. Data scientists own data analysis, this is our profession. Sometimes, we need to create interactive visualizations to communicate our work.
Our audience is increasingly diverse: analytics product owners, researchers, journalists, general public are just a few examples. How do we make sure our visualizations are maximally understandable and usable by our target audience?

### March 01, 2015

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11:24 PM | A nice cuppa

Q: What do you think about this new research on tea preventing diabetes? A: That’s not what it says Q: Sure it is. Big black letters, right at the top: “Three cups of tea a day can cut your risk of diabetes… even if you add milk” A: I mean that’s not what the research […]

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10:56 PM | Nimoy tribute on MeTV

One of these days, I would love to spend some time discussing the many clever ideas of Weigel Broadcasting. (Keep in mind, Carl Reiner has called MeTV's promos "brilliant.") The company provides a fascinating case study of a well-run business.Unfortunately, this post is time-sensitive, so I'll limit myself to a quick DVR alert.I particularly recommend the Man From UNCLE episode, which also features William Shatner and Werner Klemperer and is simply a lot of fun.MeTV also ran the Star Trek […]

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10:46 PM | Visual Insight

I have another blog, hosted by the American Mathematical Society, called Visual Insight. In that blog I try to make the beauty of mathematics visible to the naked eye. I’m always looking for great images, so if you know about one, please tell me about it! Here are three of my favorite images from that […]

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7:47 PM | The invariant interval: some examples

References: Griffiths, David J. (2007), Introduction to Electrodynamics, 3rd Edition; Pearson Education – Chapter 12, Post 20-21. The invariant interval in special relativity is the scalar product of the interval between two events with itself: Since is the difference of two four-vectors, it too is a four-vector so the invariance under Lorentz transformations follows from […]

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7:11 PM | Rapidity

References: Griffiths, David J. (2007), Introduction to Electrodynamics, 3rd Edition; Pearson Education – Chapter 12, Post 19. An alternative way of writing the Lorentz transformations is to define a quantity called the rapidity: Using this definition, we have since . Also so This is similar to a rotation through an angle in 3-d space, except […]

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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 […]