Loops in R: Think different

November 15, 2010
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Especially for programmers that come to R from other languages, R sometimes gets dinged about the speed of its for loops. But a lot of the time, where you might have needed an iterative loop in another language to solve a specific task, you don't need a for loop in R at all. Often, there's a pre-build function to...

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Example 8.14: generating standardized regression coefficients

November 15, 2010
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Example 8.14: generating standardized regression coefficients

Standardized (or beta) coefficients from a linear regression model are the parameter estimates obtained when the predictors and outcomes have been standardized to have variance = 1. Alternatively, the regression model can be fit and then standardized ...

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Feature selection: All-relevant selection with the Boruta package

November 15, 2010
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Feature selection: All-relevant selection with the Boruta package

Feature selection is an important step for practical commercial data mining which is often characterised by data sets with far too many variables for model building. There are two main approaches to selecting the features (variables) we will use for the analysis:...

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Feature selection: All-relevant selection with the Boruta package

November 15, 2010
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Feature selection: All-relevant selection with the Boruta package

Feature selection is an important step for practical commercial data mining which is often characterised by data sets with far too many variables for model building. There are two main approaches to selecting the features (variables) we will use for the analysis:...

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Isarithmic History of the Two-Party Vote

November 15, 2010
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Isarithmic History of the Two-Party Vote

A few weeks ago, I shared a series of choropleth maps of U.S. presidential election returns, illustrating the relative support for Democratic, Republican, and third Party candidates since 1920. The granularity of these county level results led me to wonder whether it would be possible to develop an isarithmic map of presidential voting using the … Continue reading →

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Introducing Monte Carlo in PaRis

November 14, 2010
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Introducing Monte Carlo in PaRis

As already announced on Statisfaction, I will start a short course in English based on Introducing Monte Carlo Methods with R at ENSAE next Tuesday. The slides were written by George Casella for a course he gave in Italy last spring and he kindly agreed on making them available on slideshare: Filed under:

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ZAT! 2010

November 13, 2010
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Tomorrow is the last day to enjoy the first edition of Montpellier's ZAT! (Zones Artistiques Temporaires). I was there this afternoon and tonight, but I found it much more picture worthy tonight: Other people have also taken pictures and sha...

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Reporting Standard Errors for USL Coefficients

November 13, 2010
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In a recent Guerrilla CaP Group discussion, Baron S. wrote:....BS> Using gnuplot against the dataset I gave, I get BS>    sigma   0.0207163 +/- 0.001323 (6.385%) BS>    kappa   0.000861226 +/- 5.414e-05 (6.287%) The Gnuplot output includes the errors for each of the universal scalability law (USL) coefficients. A question about the magnitude of...

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Reporting Standard Errors for USL Coefficients

November 13, 2010
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In a recent Guerrilla CaP Group discussion, Baron S. wrote:....BS> Using gnuplot against the dataset I gave, I get BS>    sigma   0.0207163 +/- 0.001323 (6.385%) BS>    kappa   0.000861226 +/- 5.414e-05 (6.287%) The Gnuplot output includes the errors for each of the universal scalability law (USL) coefficients. A question about the magnitude of...

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My Day at ACM Data Mining Camp III

November 13, 2010
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My Day at ACM Data Mining Camp III

My first time at ACM Data Mining Camp was so awesome, that I was thrilled the make the trip up to San Jose for the November 2010 version. In July, I gave a talk at the Emerging Technologies for Online Learning Symposium conference with a faculty member in the Department of Statistics, at the Fairmont. The place was amazing,...

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New R Users Group for University of Utah and Research Park

November 13, 2010
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I’m organizing a new R Users Group for the University of Utah and Research Park sponsored by the Study Design and Biostatistics Center. We welcome all to come. The first meeting will be dedicated to finding out what users needs and abilities are. We also welcome all skill levels. But I will also give a

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Know any R blogs in your own language?

November 13, 2010
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Know any R blogs in your own language?

A happy announcement Hello everyone. After playing around with the idea of extending R-bloggers to languages other then English, today I went a head and did it. The new sub-site can be found at: http://www.r-bloggers.com/lang/ So far it offers the content of only 3 4 bloggers, writing posts about R in Indonesian, Italian, Dutch and Korean. Asking for help As opposed to...

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Programming with R – Checking Data Types

November 13, 2010
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There are a number of useful functions in R that test the variable type or convert between different variable types. These can be used to validate function input to ensure that sensible answers are returned from a function or to ensure that the function doesn’t fail. Following on from a previous post on a simple function

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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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