Because it’s Friday: Asteroids

November 12, 2010
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A huge mass of rock hurtling in from space could really make a mess of your weekend plans. So it's comforting to know that the world's astronomers are out there keeping an eye for any potential earth-grazers. See their discoveries over the past 30 years in this beautifully-designed animation: Earth crossers are in red; earth approachers are in yellow;...

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New R User Group in Cincinnati / Dayton

November 12, 2010
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The latest local R user group to join the fold is CinDay RUG, serving the Cincinnati/Dayton area in Ohio. The group was founded by Stu Rodgers, who decided to set it up after posting a query on LinkedIn and finding several other R users in the area. Even if you think there's not enough likeminded folks in your area...

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Update: Forbes wants your R stories by Nov 17

November 12, 2010
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I mentioned recently that Forbes is seeking stories about R for a forthcoming issue. Well, the story will now be in the December issue (bumped up from the January issue), so be sure to get your post your stories about R to the Mean Business blog by November 17. Forbes: Names You Need to Know in 2011: R Data...

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Risk-Opportunity Analysis

November 12, 2010
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Risk-Opportunity Analysis

I will be attending Ralph Vince's risk-opportunity analysis workshop in Tampa this weekend.  Drop me a note if you're in the area and would like to meet for coffee / drinks.

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What would impressionnists do with R ?

November 12, 2010
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What would impressionnists do with R ?

I've been playing with images recently, probably inspired from my trip in San Francisco. There was an exhibit at the De Young museum of fine arts with pieces borrowed from the Musée d'Orsay. I did not go to the exhibit because it is easy enough fo...

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Bayesian Inference for Latent Gaussian Models

November 12, 2010
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Bayesian Inference for Latent Gaussian Models

An exciting conference in Zurich next February, 02-05. (I think I will attend! And not for skiing reasons!) Latent Gaussian models have numerous applications, for example in spatial and spatio-temporal epidemiology and climate modelling. This workshop brings together researchers who develop and apply Bayesian inference in this broad model class. One methodological focus is on

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Speeding up Optmatch while improving match quality

November 12, 2010
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“Fast, cheap, correct: Pick two.” Does this phrase apply to statistical matching algorithms? In the case of Optmatch, you can have all three. “Cheap” is easy: it is open source. You can download it for free. Today I’m going to explain how to make the matching process both faster and more substantively relevant using a technique we call...

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How to calculate confidence intervals of correlations with R

November 11, 2010
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This post sets out how to calculate confidence intervals for correlations using R. Because I often get this question from people unfamiliar with R, it assumes no prior knowledge of R. Formulas Online Statsbookhas formulas for calculating the confiden...

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How to calculate confidence intervals of correlations with R

November 11, 2010
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This post sets out how to calculate confidence intervals for correlations using R. Because I often get this question from people unfamiliar with R, it assumes no prior knowledge of R. Formulas Online Statsbookhas formulas for calculating the confiden...

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RcppArmadillo 0.2.9

November 11, 2010
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The new version 0.2.9 of RcppArmadillo has been uploaded to CRAN. The only change is an update of the included Armadillo template library to version 0.9.92 which Conrad released this week. RcppArmadillo makes it easy to write highly efficient and hi...

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Remembering on 11/11

November 11, 2010
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Remembering on 11/11

Today is Veterans Day in the US, and Remembrance Day or Armistice Day elsewhere in the world. Whatever you know this day as, it's a day for remembering the sacrifices of those who served. Drew Conway has commemorated the day in a touching yet saddening way, by visualizing with R the sparse distribution of funds to support the many...

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Help Mozilla visualize how people use Firefox

November 11, 2010
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Help Mozilla visualize how people use Firefox

You might recall we posted a couple of weeks ago this chart summarizing the times of the day Firefox users switch on Private Browsing mode: The chart, based on data from the Mozilla Test Pilot program tells an interesting story about the habits of Web users. But what other interesting stories could be told, to reveal more insights into...

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Also in Bosnia & Herzegovina, satisfied parents are those who believe their school representatives are effective

November 11, 2010
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In the mixed effects regression for all 10 countries in the research I mentioned previously on this blog http://stevepowell99.posterous.com/which-parents-are-satisfied-with-their-childs, while school mean of “parents believing their representatives are effective” was significantly positively related to their overall satisfaction with education, this effect was dwarfed by the contribution of this variable at individual level, even when allowing

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Also in Bosnia & Herzegovina, satisfied parents are those who believe their school representatives are effective

November 11, 2010
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In the mixed effects regression for all 10 countries in the research I mentioned previously on this blog http://stevepowell99.posterous.com/which-parents-are-satisfied-with-their-childs, while school mean of "parents believing their represen...

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R is a name you need to know

November 11, 2010
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R is a name you need to know

As if that is news to some of you. Forbes has a Mean Business blog post by Steve McNally titled “Names You Need to Know in 2011: R Data Analysis Software”. The post includes several links to why R is wonderful. It also includes a pretty — but seemingly useless — statistical graph.  Correct me … Continue reading...

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Mortgage Calculator (and Amortization Charts) with R

November 10, 2010
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Mortgage Calculator (and Amortization Charts) with R

Mortgage rates have been at historic lows recently.  The rates are posted various places online along with simple mortgage calculators.  Such calculators illustrate the payment schedule for a mortgage based upon selected terms. But with less ...

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Mortgage Calculator (and Amortization Charts) with R

November 10, 2010
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Mortgage Calculator (and Amortization Charts) with R

Mortgage rates have been at historic lows recently.  The rates are posted various places online along with simple mortgage calculators.  Such calculators illustrate the payment schedule for a mortgage based upon selected terms. But with less ...

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New ebook: Asian Option Pricing with R/Rmetrics

November 10, 2010
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(This article was first published on Rmetrics blogs, and kindly contributed to R-bloggers) To leave a comment for the author, please follow the link and comment on his blog: Rmetrics blogs. R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web...

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Tell Forbes how you use R

November 10, 2010
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Steve McNally of the Forbes Mean Business blog says R is a name you need to know for 2011. He cites some great examples of R in action: Facebook has used R to figure out that “just two data points are significantly predictive of whether a user remains on Facebook: (i) having more than one session as a new...

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Bayesian estimation with Markov Chain Monte Carlo using PyMC

November 10, 2010
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Prof. Chris Fonnesbeck briefly introduces Bayesian inference, then discusses how to estimate Bayesian models with Markov Chain Monte Carlo using PyMC. PyMC is the premier Python package for doing MCMC estimation, and Prof. Fonnesbeck is one of the pac...

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Quantitative Ecology 2010-11-10 14:56:00

November 10, 2010
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At last... I have been suffering with XEmacs displaying odd characters instead of the quotation marks that are used in R help files. This was driving me up the wall because it makes the files (and R output in general) very hard to read; however, I fina...

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Quantitative Ecology 2010-11-10 14:56:00

November 10, 2010
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At last... I have been suffering with XEmacs displaying odd characters instead of the quotation marks that are used in R help files. This was driving me up the wall because it makes the files (and R output in general) very hard to read; however, I fina...

Read more »

Co-authorship Network of SSRN Conflict Studies eJournal

November 10, 2010
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As part of my on-going research simulating network structure using graph motifs I have been collecting novel data sets to test and benchmark the method. Since I am a political scientist studying conflict, it was suggested to me to collect a co-authorship network within this sub-discipline. Such a network is useful for several reasons;

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Generating a quasi Poisson distribution, version 2

November 10, 2010
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Generating a quasi Poisson distribution, version 2

Here and there, I mentioned two codes to generated quasiPoisson random variables. And in both of them, the negative binomial approximation seems to be wrong. Recall that the negative binomial distribution is where and in R, a negative binomial di...

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Don’t be a Turkey

November 9, 2010
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Don’t be a Turkey

'Indeed, I am moving on: my new project is about methods on how to domesticate the unknown, exploit randomness, figure out how to live in a world we don't understand very well. While most human thought (particularly since the enlightenment) has focused us on how to turn knowledge into decisions, my new mission is to...

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Don’t be a Turkey

November 9, 2010
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Don’t be a Turkey

'Indeed, I am moving on: my new project is about methods on how to domesticate the unknown, exploit randomness, figure out how to live in a world we don't understand very well. While most human thought (particularly since the enlightenment) has focused us on how to turn knowledge into decisions, my new mission is to...

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Forecast estimation, evaluation and transformation

November 9, 2010
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Forecast estimation, evaluation and transformation

I’ve had a few emails lately about forecast evaluation and estimation criteria. Here is one I received today, along with some comments. I have a rather simple question regarding the use of MSE as opposed to MAD and MAPE. If the parameters of a time series model are estimated by minimizing MSE, why do we

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Particle learning [rejoinder]

November 9, 2010
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Particle learning [rejoinder]

Following the posting on arXiv of the Statistical Science paper of Carvalho et al., and the publication by the same authors in Bayesian Analysis of Particle Learning for general mixtures I noticed on Hedibert Lopes’ website his rejoinder to the discussion of his Valencia 9 paper has been posted. Since the discussion involved several points

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Any R packages to solve Vehicle Routing Problem?

November 9, 2010
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Any R packages to solve Vehicle Routing Problem?

Are there any R packages to solve Vehicle Routing Problem (VRP)?I looked around but could not find any... Any leads?VRP is a classic combinatorial optimization challenge and has been an active area of research for operations research gurus fo...

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