Monthly Archives: September 2013

Fun With Just-In-Time Compiling: Julia, Python, R and pqR

September 2, 2013
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Fun With Just-In-Time Compiling: Julia, Python, R and pqR

Recently I’ve been spending a lot of time trying to learn Julia by doing the problems at Project Euler. What’s great about these problems is that it gets me out of my normal design patterns, since I don’t generally think about prime numbers, factorials and other number theory problems during my normal workday. These problems Fun With Just-In-Time...

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Sentiment Analysis on Twitter with Viralheat API

September 2, 2013
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Sentiment Analysis on Twitter with Viralheat API

Hi there! Some time ago I published a post about doing a sentiment analysis on Twitter. I used two wordlists to do so; one with positive and one with negative words. For the first try of a sentiment analysis it is surely a good way to start but if you want to receive more accurate …

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Poll: R top language for data science three years running

September 2, 2013
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Poll: R top language for data science three years running

KDDNuggets has completed its annual poll of top languages for analytics, data mining and data science, and just as in the prior two years the R language is ranked the most popular. R is used by almost 61% of respondents: R's usage grew year over year as well, up 16% compared to the 2012 poll. By contrast, the rate...

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Showing results from Cox Proportional Hazard Models in R with simPH

September 2, 2013
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Showing results from Cox Proportional Hazard Models in R with simPH

Effectively showing estimates and uncertainty from Cox Proportional Hazard (PH) models, especially for interactive and non-linear effects, can be challenging with currently available software. So, researchers often just simply display a results table. These are pretty useless for Cox PH models. It is difficult to decipher a simple linear variable’s estimated effect and basically impossible to understand time...

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Passing-Bablok Regression: R code for SAS users

September 2, 2013
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Passing-Bablok Regression: R code for SAS users

While at the Joint Statistical Meeting a few weeks ago I was talking to a friend about various aspects to clinical trials. He indicated that no current R package was able to perfectly reproduce Passing-Bablok (PB) regression so that it exactly matched SAS. He ultimately wrote a couple of functions and kindly shared them with

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Easy 3-Minute Guide to Making apply() Parallel over Distributed Grids and Clusters in R

September 1, 2013
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Easy 3-Minute Guide to Making apply() Parallel over Distributed Grids and Clusters in R

Last week I attended a workshop on how to run highly parallel distributed jobs on the Open Science Grid (osg). There I met Derek Weitzel who has made an excellent contribution to advancing R as a high performance computing language by developing BoscoR. BoscoR greatly facilitates the use of the already existing package “GridR” by The post Easy...

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Latent Variable Analysis with R: Getting Setup with lavaan

September 1, 2013
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Latent Variable Analysis with R: Getting Setup with lavaan

Getting Started with Structural Equation Modeling Part 1Getting Started with Structural Equation Modeling: Part 1 Introduction For the analyst familiar with linear regression fitting structural equation models can at first feel strange. In the R environment, fitting structural equation models involves learning new modeling syntax, new plotting...

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Fair weather fans, redux

September 1, 2013
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Fair weather fans, redux

Fair weather fans, redux Or, A little larger small sample On August 11 the Victoria HarbourCats closed out their 2013 West Coast League season with a 4-3 win over the Bellingham Bells. In an earlier...

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Mixed models exercise 2. Repeated measurements

September 1, 2013
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Continuing my exploration of mixed models, I now understand what is happening in the second SAS(R)/STAT example for proc mixed (page 5007 of the SAS/STAT 12.3 Manual). It is all about correlation between the time-points within subjects. The data as suc...

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