Monthly Archives: October 2011

The Skills of a Data Miner

October 9, 2011
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Data mining is not only statistics, even if statistics is the most recognized academic component of it. It also includes data cleaning, machine learning and data visualization. The scarce factor is the ability to understand that data and extract value ...

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Equality of Covariances Matrices Test in R (varcomp)

October 9, 2011
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Equality of Covariances Matrices Test in R (varcomp)

This is a piece of code I implemented in 2004, which was supposed to be part of an R-package in multivariate testing (to be named, rather creatively, mvttests). Time has flown, I haven’t still got around to implementing the said package, but people keep asking me for the varcomp function, so here it is, for

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understanding computational Bayesian statistics

October 9, 2011
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understanding computational Bayesian statistics

I have just finished reading this book by Bill Bolstad (University of Waikato, New Zealand) which a previous ‘Og post pointed out when it appeared, shortly after our Introducing Monte Carlo Methods with R. My family commented that the cover was nicer than those of my own books, which is true. Before I launch into

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Sphericity Test for Covariance Matrices in R (sphericity.test)

October 9, 2011
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Sphericity Test for Covariance Matrices in R (sphericity.test)

This is a piece of code I implemented in 2004, which was supposed to be part of an R-package in multivariate testing (to be named, rather creatively, mvttests). Time has flown, I haven’t still got around to implementing the said package, but people keep asking me for the sphericity.test function, so here it is, for

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Operating on datasets inside a function

October 9, 2011
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There are times when we need to write a function that makes changes to a generic data frame that is passed as an argument. Let’s say, for example, that we want to write a function that converts to factor any … Continue reading →

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Open Street maps

October 8, 2011
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Open Street maps

There have been some exciting developments in the Deducer ecosystem over the summer which should go into CRAN release in the next few months. Today I'm going to give a quick sneak peek at an Open Street Map - R connection with accompanying GUI. This post will just show the non-GUI components. The first part of the

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Performance difference between Stata and R

October 8, 2011
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With respect to multinomial logit model, the performance difference between the two packages are quite large, based on this post.

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Some light data munging with R, with an application to ranking NFL Teams

October 8, 2011
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Some light data munging with R, with an application to ranking NFL Teams

I recently submitted this blog to R-bloggers, which aggregates R-related blog posts. It's a fantastic site and has been invaluable to me as I've learned R. One of my favorite kinds of articles is the hands-on, "hello world"-style weekend project t...

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Visualizing GIS data with R and Open Street Map

October 8, 2011
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Visualizing GIS data with R and Open Street Map

In this post I way to share with you some code to use Openstreetmap – maps as a backdrop for a data visualization. We will use the RgoogleMaps-package for R. In the following I will show you how to make this graph. 1. Download the map I wanted to take a closer look at an

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A brief idea of style

October 8, 2011
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Once one starts writing more R code the need for consistency increases, as it facilitates managing larger projects and their maintenance. There are several style guides or suggestions for R; for example, Andrew Gelman’s, Hadley Wickham’s, Bioconductor’s and this one. … Continue reading →

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