Correlation is evidence of causation

February 20, 2014
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Correlation is evidence of causation

In class last week, I was talking about correlation and linear regression, and I made the outrageous claim that correlation is evidence of causation.  One of my esteemed colleagues, who is helping out with the class, was sitting in the back of the...

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Data Analysis for Genomics MOOC

February 20, 2014
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Data Analysis for Genomics MOOC

Last month I told you about Coursera's specializations in data science, systems biology, and computing. Today I was reading Jeff Leek's blog post defending p-values and found a link to HarvardX's Data Analysis for Genomics course, taught by Rafael Iriz...

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Do differences between biology and statistics explain some of our diverging attitudes regarding criticism and replication of scientific claims?

February 20, 2014
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Do differences between biology and statistics explain some of our diverging attitudes regarding criticism and replication of scientific claims?

Last month we discussed an opinion piece by Mina Bissell, a nationally-recognized leader in cancer biology. Bissell argued that there was too much of a push to replicate scientific findings. I disagreed, arguing that scientists should want others to be able to replicate their research, that it’s in everyone’s interest if replication can be done […]The post Do differences between biology and statistics explain some of our diverging attitudes regarding…

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R.A. Fisher: ‘Two New Properties of Mathematical Likelihood’

February 20, 2014
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R.A. Fisher: ‘Two New Properties of Mathematical Likelihood’

Exactly 1 year ago: I find this to be an intriguing discussion–before some of the conflicts with N and P erupted.  Fisher links his tests and sufficiency, to the Neyman and Pearson lemma in terms of power.  It’s as if we may see them as ending up in a similar place while starting from different […]

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More on Product Terms and Interaction in Logistic Regression Models

February 20, 2014
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I noticed that Bill Berry, Justin Esarey, and Jackie DeMeritt's (BDE) long-time R&R'ed paper at AJPS is finally forthcoming. I really like seeing highly applied, but rigorous, work like this being published at top journals. You should definitely have a look at their paper if you use logit or probit models to argue for interaction. […]

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R in Insurance 2014 Conference Poster

February 20, 2014
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R in Insurance 2014 Conference Poster

Here is the poster for the 2nd R in Insurance conference on Monday 14 July 2014 at Cass Business School in London:R in Insurance 2014 conference poster. Download PDF versionImportant dead lines to keep in mind:Abstract submissions: 28 March 2014Early b...

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Backcasting in R

February 20, 2014
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Backcasting in R

Sometimes it is useful to “backcast” a time series — that is, forecast in reverse time. Although there are no in-built R functions to do this, it is very easy to implement. Suppose x is our time series and we want to backcast for periods. Here is some code that should work for most univariate time series. The example is non-seasonal, but the code will also work with seasonal data.…

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Identification of ARMA processes

February 20, 2014
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Last week (in the MAT8181 course) in order to identify the orders of an ARMA process, we’ve seen the eacf method, and I mentioned the scan method, introduced in Tsay and Tiao (1985). The code below – to produce the output of the scan proce...

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evaluating stochastic algorithms

February 19, 2014
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evaluating stochastic algorithms

Reinaldo sent me this email a long while ago Could you recommend me a nice reference about measures to evaluate stochastic algorithms (in particular focus in approximating posterior distributions). and I hope he is still reading the ‘Og, despite my lack of prompt reply! I procrastinated and procrastinated in answering this question as I did not […]

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Selfie City: a Visualization-Centric Analysis of Online Self-Portraits

February 19, 2014
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Selfie City: a Visualization-Centric Analysis of Online Self-Portraits

Selfie City [selfiecity.net], developed by Lev Manovich, Moritz Stefaner, Mehrdad Yazdani, Dominikus Baur and Alise Tifentale, investigates the socio-popular phenomenon of self-portraits (or selfies) by using a mix of theoretic, artistic and quantitat...

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Why do we love R so much?

February 19, 2014
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When Jeff, Brian, and I started the Johns Hopkins Data Science Specialization we decided early on to organize the program around using R. Why? Because we love R, we use it everyday, and it has an incredible community of developers … Continue reading →

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The replication and criticism movement is not about suppressing speculative research; rather, it’s all about enabling science’s fabled self-correcting nature

February 19, 2014
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Jeff Leek points to a post by Alex Holcombe, who disputes the idea that science is self-correcting. Holcombe writes [scroll down to get to his part]: The pace of scientific production has quickened, and self-correction has suffered. Findings that might correct old results are considered less interesting than results from more original research questions. Potential […]The post The replication and criticism movement is not about suppressing speculative research; rather, it’s…

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R: Fun with surf3D function

February 19, 2014
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R: Fun with surf3D function

There is one package that I've been longing. A package that will give me the power to manipulate and do any 3D stuffs in R. I tried persp and wireframe, but I find them difficult to use especially on complicated mathematical functions, like doing param...

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Voting Twice in France

February 19, 2014
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On the Monkey Cage blog, Baptiste Coulmont (a.k.a. @coulmont) recently uploaded a post entitled “You can vote twice ! The many political appeals of proxy votes in France“, coauthored with Joël Gombin (a.k.a. @joelgombin), and myself....

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Techniques for scoring a regression model in SAS

February 19, 2014
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Techniques for scoring a regression model in SAS

My previous post described how to use the "missing response trick" to score a regression model. As I said in that article, there are other ways to score a regression model. This article describes using the SCORE procedure, a SCORE statement, the relatively new PLM procedure, and the CODE statement. [...]

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Global energy forecasting competitions

February 19, 2014
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Global energy forecasting competitions

The 2012 GEFcom competition was a great success with several new innovative forecasting methods introduced. These have been published in the IJF as follows: Hong, Pinson and Fan. Global Energy Forecasting Competition 2012 Charleton and Singleton. A refined parametric model for short term load forecasting Lloyd. GEFCom2012 hierarchical load forecasting: Gradient boosting machines and Gaussian processes Nedelec, Cugliari and Goude: GEFCom2012: Electric load forecasting and backcasting with semi-parametric models Ben Taieb and Hyndman. A…

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Off to New Zealand in July

February 19, 2014
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Off to New Zealand in July

The New Zealand Association of Economists is holding its 55th annual conference in early July of this year, in Auckland.I'm delighted that I'll be there as a keynote speaker. The very first conference presentation that I made was at the meeting of...

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Update on Dataviz Workshop 1

February 19, 2014
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Update on Dataviz Workshop 1

Happy to report on the dataviz workshop, a first-time offering at NYU. I previously posted the syllabus here. I made minor changes to the syllabus, adding Alberto Cairo's book, The Functional Art (link), as optional reading, some articles from the...

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Aris Spanos: The Enduring Legacy of R. A. Fisher

February 19, 2014
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Aris Spanos: The Enduring Legacy of R. A. Fisher

More Fisher insights from A. Spanos, this from 2 years ago: One of R. A. Fisher’s (17 February 1890 — 29 July 1962) most re­markable, but least recognized, achievement was to initiate the recast­ing of statistical induction. Fisher (1922) pioneered modern frequentist statistics as a model-based approach to statistical induction anchored on the notion of a […]

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Bivariate Densities with N(0,1) Margins

February 19, 2014
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This Monday, in the ACT8595 course, we came back on elliptical distributions and conditional independence (here is an old post on de Finetti’s theorem, and the extension to Hewitt-Savage’s). I have shown simulations, to illustrate those two...

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Slime-Based Maps Simulate Real-World Transportation Networks

February 18, 2014
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Slime-Based Maps Simulate Real-World Transportation Networks

Several research groups around the world in the area of mobility and transportion optimization are exploring the use of a particular slime mould, Physarum polycephalum (the "many-headed slime"), to establish the most efficient routes around congested ...

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3D Globe Visualizes the Flows of Food-Aid Funding among Countries

February 18, 2014
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3D Globe Visualizes the Flows of Food-Aid Funding among Countries

WFP: Country Donors and Recipients [wfp.org] by Santiago Ortiz shows all World Food Programme (WFP) funding from 2003 to present as flows among individual countries. Each country on the low-polygon count, interactive 3D globe can be selected, in orde...

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k-means clustering in a GIF

February 18, 2014
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k-means clustering in a GIF

k-means is a simple and intuitive clustering approach. Here is a movie showing how it works:

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