Interactive Graphics with the iplots Package (from “R in Action”)

January 24, 2012
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Interactive Graphics with the iplots Package (from “R in Action”)

(This article was first published on R-statistics blog » R, and kindly contributed to R-bloggers) The followings introductory post is intended for new users of R.  It deals with interactive visualization using R through the iplots package. This is a guest article by Dr. Robert I. Kabacoff, the founder of (one of) the first online R tutorials websites: Quick-R. Kabacoff has...

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Analyzing US Government Contract Awards in R

January 23, 2012
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Analyzing US Government Contract Awards in R

As I was exploring open data sources, I came across USA spending. This site contains information on US government contract awards and other disbursements, such as grants and loans. In this post, we will look at data on contracts awarded in the state of Maryland in the fiscal year 2011, which is available by selecting "Maryland"...

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ACT to SAT M+V Concordance Chart in R

January 23, 2012
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For those of who work in Enrollment Management and routinely analyze higher ed data, I wanted to share an easy way to convert ACT to equivalent SAT M+V scores in R. I am dynamically building a dataset that uses the concordance chart located here. Simply, use this data frame and merge it onto your existing

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New R User Group in Belgium

January 23, 2012
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RBelgium is the latest local R user group to join the R community. Led by R user Jean-Baptiste Poullet, the group will host meetings on the first Friday of each month at the Alfot Hotel in Brussels, as well as weekly coffee get-togethers. The group also provides an on-line discussion forum on statistics and applications with R. You can...

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Flight mapping in R

January 23, 2012
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Flight mapping in R

This map has been produced before (and much better) by others but who cares. This effort was achieved purely via the standard R plot function*. I believe the only departure from predecessor maps has been to order the list by … Continue reading →

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My first R package: parallel differential evolution

January 23, 2012
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My first R package: parallel differential evolution

Last night I was working on a difficult optimization problems, using the wonderful DEoptim package for R. Unfortunately, the optimization was taking a long time, so I thought I'd speed it up using a foreach loop, which resulted in the fo...

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Marketing Mix Lab: Visualising The Correlation Matrix

January 23, 2012
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Marketing Mix Lab: Visualising The Correlation Matrix

Following on from the previous post here is an R function for visualising correlations between the explanatory variables in your data set. An interesting example is the North Carolina Crime data set that comes with the plm package. This has the following continuous variables: crmrte crimes committed per person prbarr probability of arrest prbarr probability … Continue reading...

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The distribution of financial returns made simple

January 23, 2012
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The distribution of financial returns made simple

Why returns have a stable distribution As “A tale of two returns” points out, the log return of a long period of time is the sum of the log returns of the shorter periods within the long period. The log return over a year is the sum of the daily log returns in the year.  … Continue reading...

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RNetLogo – A package for running NetLogo from R

January 23, 2012
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Described in a new Methods in Ecology and Evolution paper here, a new R package RNetLogo allows you to use NetLogo from R. NetLogo is software is a "multi-agent programmable modeling environment". NetLogo can be used in individual- and agent-based mod...

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Starburst in R

January 22, 2012
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> starburst('Matrices!') M M M a a a t t t rrr Matrices! ccc e e e s s s ! ! ! wrathematic led me FibBuzz, which led me to 

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Even odds

January 22, 2012
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Even odds

This evening, I found a nice probabilistic puzzle on http://www.futilitycloset.com/ "A bag contains 16 billiard balls, some white and some black. You draw two balls at the same time. It is equally likely that the two will be the same color as diff...

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Some Rcpp benchmarks

January 22, 2012
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I ran the Fibonacci number example from the Rcpp package on a number of computers and operating systems. Here are the results:A. On my main computer (Core 2 Extreme 3.06GHz, 8 GB memory) running Ubuntu 10.04 (g++ 4.4.3):        test...

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Simulating average height of a random binary search tree

January 22, 2012
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Simulating average height of a random binary search tree

Recently on Stack Overflow I have found a discussion on Average height of a binary search tree. The problem has been solved analytically, see for example Reed (2003). However, I was intrigued by one of the answers that presented a simulation ...

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Cluster your Facebook friends

January 22, 2012
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Cluster your Facebook friends

Last week, I came across two interesting posts by Romain François and Petr Simecek: Crawling Facebook with R, in which Romain explains how to connect to the Facebook Graph API Mining Facebook Data: Most “Liked” Status and Friendship Network, in which Petr use Romain’s function to visualize your friend’s network. As coincidence would have it, I also came across an...

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Time Series Intervention Analysis wih R and SAS

January 21, 2012
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Time Series Intervention Analysis wih R and SAS

In a previous post, I worked through the theory behind intervention analysis. In his time series course, University of Georgia political science professor Jamie Monogan demonstrates how to implement intervention analysis in R.  The following examp...

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Lessons learned from a recent R package submission

January 21, 2012
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Lessons learned from a recent R package submission

R has zillions of packages, and people are submitting new ones each day. The volunteers who keep R going are doing an incredibly useful service to the profession, and they’re busy. A colleague sends in some suugestions based on a recent experience with a package update: 1. Always use the R dev version to write The post Lessons...

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Ten reasons to love the cloud

January 21, 2012
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Ten reasons to love the cloud: The names on Heroku. empty-moon-9726. Suddenly the cloud seems prosaic when you can have the moon. Being reunited with putty. It’s like catching up with an old friend. At first the conversation is a little stilted, but then you soon remember just how well you got on and what brought you together in the first...

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Initial thanks

January 21, 2012
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Starting this blog with initial thanks to Josh Suereth from whom I cloned the template of this blog, Tom Preston-Werner who made Jekyll (a static site generator for this blog), Scott Chamberlain who made me aware of it.

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A Quick View Over a MASHe Google Spreadsheet Twitter Archive of UKGC12 Tweets

January 20, 2012
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A Quick View Over a MASHe Google Spreadsheet Twitter Archive of UKGC12 Tweets

Following on from A Tool Chain for Plotting Twitter Archive Retweet Graphs – Py, R, Gephi, here’s a quick view summary view over #UKGC12 tweets saved in Google Spreadsheet archive as developed by Martin Hawksey, generated from an R script (R code available here; #ukgc12 tweet archive here)… (I did mean to tidy these up,

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Separation of degrees

January 20, 2012
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Separation of degrees

Scientific American has a short article on trends in undergraduate degrees over the past 20 years, illustrated with a great infographic by Nathan Yau. As a big fan of STEM (science, tech, engineering and math) education, I was pleased to … Continue reading →

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R Regression Diagnostics Part 1

January 20, 2012
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R Regression Diagnostics Part 1

Linear regression can be a fast and powerful tool to model complex phenomena. However, it makes several assumptions about your data, and quickly breaks down when these assumptions, such as the assumption that a linear relationship exists between the predictors and the dependent variable, break down. In this post, I will introduce some diagnostics that you can...

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Time Series Matching with Dynamic Time Warping

January 20, 2012
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Time Series Matching with Dynamic Time Warping

THIS IS NOT INVESTMENT ADVICE. The information is provided for informational purposes only. In the Time Series Matching post, I used one to one mapping to the compute distance between the query(current pattern) and reference(historical time series). Following chart visualizes this concept. The distance is the sum of vertical lines. An alternative way to map

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MAT8886 Extremes and sums (of i.i.d. random variables)

January 20, 2012
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MAT8886 Extremes and sums (of i.i.d. random variables)

Yesterday, we have discussed briefly sums and maximas of i.i.d. random variables using the concept of subexponential distributions. Today, we will introduce the concept of regular variation: a positive function is said to be regularly varying (at i...

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Object Oriented Programming in R

January 20, 2012
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As someone who was a Java programmer for many years learning R’s object oriented programming framework has been frustrating to say the least. I like the simplicity of S3 but find it limiting when you wish to write methods that change the underlying data elements. That is, printing, summarizing, and plotting work great because they

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Hadley Wickham goes behind the scenes on ggplot2

January 20, 2012
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Hadley Wickham goes behind the scenes on ggplot2

Hadley Wickham, creator of the ggplot2 packages for R (as well as several others) will present a webinar on February 8 going behind the scenes of the popular graphics package. If you've never used ggplot2 before, this will be a great way to learn about the kinds of charts you can create with it; and if you're a regular...

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R Regression Diagnostics Part 1

January 20, 2012
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R Regression Diagnostics Part 1

Linear regression can be a fast and powerful tool to model complex phenomena. However, it makes several assumptions about your data, and quickly breaks down when these assumptions, such as the assumption that a linear relationship exists between the predictors and the dependent variable, break down. In this post, I will introduce some diagnostics that you can perform to...

Read more »

Object Oriented Programming in R

January 20, 2012
By

As someone who was a Java programmer for many years learning R’s object oriented programming framework has been frustrating to say the least. I like the simplicity of S3 but find it limiting when you wish to write methods that change the underlyi...

Read more »

Object Oriented Programming in R

January 20, 2012
By

As someone who was a Java programmer for many years learning R’s object oriented programming framework has been frustrating to say the least. I like the simplicity of S3 but find it limiting when you wish to write methods that change the underlyi...

Read more »

Power and Sample Size for Repeated Measures ANOVA with R

January 20, 2012
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Power and Sample Size for Repeated Measures ANOVA with R

Background One of my colleagues is an academic physical therapist (PT), and he's working on a paper to his colleagues related to power, sample size, and navigating the thicket of trouble that surrounds those two things. We recently got together to walk through some of the issues, and I thought I would share some of the wildlife we observed...

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