4159 search results for "git"

Label placement with spplot and lattice

December 28, 2012
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Label placement with spplot and lattice

The package maptools includes new functions to label points and labels. Line labelling The lineLabel function produces and draws text …Continuar leyendo »

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Who Survived on the Titanic? Predictive Classification with Parametric and Non-parametric Models

December 24, 2012
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Who Survived on the Titanic? Predictive Classification with Parametric and Non-parametric Models

I recently read a really interesting blog post about trying to predict who survived on the Titanic with standard GLM models and two forms of non-parametric classification tree (CART) methodology. The post was featured on R-bloggers, and I think it's worth a closer look. The basic idea was to figure out which of these three

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Make a Christmas Tree in R with random ornaments/presents

December 24, 2012
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Make a Christmas Tree in R with random ornaments/presents

Happy holidays!     Link to Gist

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24 Christmas Gifts from is.R

December 24, 2012
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24 Christmas Gifts from is.R

The is.R blog has been on a roll in December with their Advent CalendaR feature: daily tips about R to unwrap each day leading up to Christmas. If you haven't been following it, start with today's post and scroll down. Sadly there isn't a tag to collect all these great posts together, but here are a few highlights: December...

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Latent Class Analysis with poLCA

December 24, 2012
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Latent Class Analysis with poLCA

On an airplane the other day, I learned of a method called latent class (transition) analysis, and it sounded like an interesting thing to try in R. Of course, as with everything R, There is a Package for That, called poLCA, written by none other than Drew Linzer (of Votamatic fame) and Jeffrey Lewis. I...

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Binary Classification – A Comparison of “Titanic” Proportions Between Logistic Regression, Random Forests, and Conditional Trees

December 23, 2012
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Binary Classification – A Comparison of “Titanic” Proportions Between Logistic Regression, Random Forests, and Conditional Trees

Now that I’m on my winter break, I’ve been taking a little bit of time to read up on some modelling techniques that I’ve never used before. Two such techniques are Random Forests and Conditional Trees.  Since both can be used … Continue reading →

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Measuring the Gerrymander with spatstat

December 23, 2012
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Measuring the Gerrymander with spatstat

Well, to be specific, I mean measuring district compactness (a very interesting subject, see these three articles for starters). There are myriad ways of measuring the “oddness” of a shape, including a comparison of the area of the district to its circumcircle, the moment of inertia of the shape, the probability that a path connecting...

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Visualizing Principal Components

December 22, 2012
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Visualizing Principal Components

Principal Component Analysis (PCA) is a procedure that converts observations into linearly uncorrelated variables called principal components (Wikipedia). The PCA is a useful descriptive tool to examine your data. Today I will show how to find and visualize Principal Components. Let’s look at the components of the Dow Jones Industrial Average index over 2012. First,

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The definitive guide to plotting confidence intervals in R

December 22, 2012
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The definitive guide to plotting confidence intervals in R

Here at is.R(), we have produced countless posts that feature plots with confidence intervals, but apparently none of those are easy to find with Google. So, today, for the purposes of SEO, we’ve put “plotting confidence intervals” in the title of our post. We also cannot resist an earnest plea from our...

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Simple data simulator for the 2PL model

December 21, 2012
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The function: This is a very simple data simulator for a 2PL Model. This is just to get you started, from here is easy to add function parameters for indicating item locations and slopes or person distribution characteristics. The function accepts on...

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