Tipping heuristics

April 28, 2010
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Tipping heuristics

INCREDIBLY SIMPLE CALCULATIONS MADE SIMPLE Yes, we all know how to calculate 15% or 20% exactly, but it’s fun to use tipping heuristics and even more fun to make crowded graphs of how they compare to each other. (Sorry for the junky chart. Open for suggestions, in the words of Tom Waits.) Here are a

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Wavelet Spectrogram Non-Stationary Financial Time Series analysis using R (TTR/Quantmod/dPlR) with USDEUR

April 28, 2010
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Wavelet Spectrogram Non-Stationary Financial Time Series analysis using R (TTR/Quantmod/dPlR) with USDEUR

I've been doing some research lately regarding types of spectral imaging and decomposition techniques that apply to non-stationary signals. As mentioned earlier, one of the major problems with the simple fourier analysis is that the basis functions ext...

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R Beginner’s Guide Book Update 4/28/2010

April 28, 2010
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R Beginner’s Guide Book Update 4/28/2010

Update: Statistical Analysis with R is now available!I am writing to update you on the progress of my R Beginner's Guide book, which is to be published through Packt. I have really gotten to work over the past couple months and have recently completed ...

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R Beginner’s Guide Book Update 4/28/2010

April 28, 2010
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R Beginner’s Guide Book Update 4/28/2010

Update: Statistical Analysis with R is now available!I am writing to update you on the progress of my R Beginner's Guide book, which is to be published through Packt. I have really gotten to work over the past couple months and have recently completed ...

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Sweave vs. pgfSweave

April 28, 2010
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Sweave vs. pgfSweave

I think pgfSweave should replace the default of Sweave system because it brings significant improvements over the original Sweave. I certain have made it my default Sweave tool on my system.------------------------------- EDITED ON MAY 1, 2010 --------...

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Eclipse and StatET – a working environment for R

April 28, 2010
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How to use Eclipse and StatET to create a handy-dandy development environment for R. Using the Eclipse environment provides a nice colored-syntax script editor, an R console, and an object browser to let you peruse the variables you've put into memory....

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Annotating Lattice Box and Whisker Plots

April 28, 2010
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Annotating Lattice Box and Whisker Plots

bwplot annotation example Sometimes you want to add a little text to box and whisker plots produced by the lattice function bwplot(). Here is one approach. Could be optimized a bit more to reduce manual specification of some elements. Suggestions...

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Analysis of Covariance – Extending Simple Linear Regression

April 28, 2010
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Analysis of Covariance – Extending Simple Linear Regression

The simple linear regression model considers the relationship between two variables and in many cases more information will be available that can be used to extend the model. For example, there might be a categorical variable (sometimes known as a covariate) that can be used to divide the data set to fit a separate linear

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Interview with Revolution CEO Norman Nie

April 28, 2010
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Steve Miller has posted his interview with Revolution's CEO Norman Nie at Information Management blogs. In the interview, Steve digs into Norman's motivations for taking on a new venture around R after his successes with SPSS and how what he learned there applies to Revolution Computing. Also up for discussion: the benefits and challenges of an open-source business model;...

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Bhapkar V test

April 28, 2010
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This is the code to perform the Bhapkar V test. I've rapidly wrote it, in 2 hours. The code is then quite brutal and it could be done better. As soon as possible, I will correct it.WARNING: it works *ONLY* with 3 groups, for now!bhapkar.test.3g sample for(i in 1:length(data1)){sample }obs for(i in 1:length(data1)){obs }rank cplets vec for(i in 1:length(data1])){vec...

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Bhapkar V test

April 28, 2010
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This is the code to perform the Bhapkar V test. I've rapidly wrote it, in 2 hours. The code is then quite brutal and it could be done better. As soon as possible, I will correct it.WARNING: it works *ONLY* with 3 groups, for now!bhapkar.test.3g sample for(i in 1:length(data1)){sample }obs for(i in 1:length(data1)){obs }rank cplets vec for(i in 1:length(data1])){vec...

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Social Network Analysis using R and Gephis

April 28, 2010
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Social Network Analysis using R and Gephis

After learning the basics of R, I decided to learn something harder last week. I picked Social Network Analysis (SNA) to learn the concepts of SNA and R. My primary interest in SNA is visual exploration of networks, so I needed to find a tool first.&n...

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Transitions in R redux

April 28, 2010
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Previously, I shared with the world a function to create a pairwise matrix of the number of transitions and transversions between two DNA sequences. Klaus Schliep kindly pointed out the possibility of a bug in the function and offered a faster, more accurate version. Thanks Klaus!titv mat res for(i...

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Transitions in R redux

April 28, 2010
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Previously, I shared with the world a function to create a pairwise matrix of the number of transitions and transversions between two DNA sequences. Klaus Schliep kindly pointed out the possibility of a bug in the function and offered a faster, more accurate version. Thanks Klaus! titv mat res for(i...

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Using R for Introductory Statistics, Chapters 1 and 2

April 27, 2010
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Using R for Introductory Statistics, Chapters 1 and 2

I'm working my way through Using R for Introductory Statistics, by John Verzani, a free version of which is available as SimpleR. Chapter 1 ...covers basics of R such as arithmetic, loading libraries and reading data. We also get an introduction to v...

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How to do this graph using R

April 26, 2010
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How to do this graph using R

I am showing three examples that will help an average R user to create beautiful graphs. The interesting (may be useful) parts of these examples are the use of some very smart but tricky functions to, for example, add a Greek symbol on a plot, add a title to a plot with some mathematical symbols. I am showing three...

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R Project and Google Summer of Code: Welcome to our students!

April 26, 2010
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A few hours ago, I sent the following to both the R development list and the informal R / GSoC list: Date: Mon, 26 Apr 2010 15:27:29 -0500 To: R Development List CC: gsoc-r Subject: R and the Google Summer of Code 2010 -- Please welcome our new st...

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R Project and Google Summer of Code: Welcome to our students!

April 26, 2010
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A few hours ago, I sent the following to both the R development list and the informal R / GSoC list: Date: Mon, 26 Apr 2010 15:27:29 -0500 To: R Development List CC: gsoc-r Subject: R and the Google Summer of Code 2010 -- Please welcome our new stud...

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R Project and Google Summer of Code: Welcome to our students!

April 26, 2010
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A few hours ago, I sent the following to both the R development list and the informal R / GSoC list: Date: Mon, 26 Apr 2010 15:27:29 -0500 To: R Development List CC: gsoc-r Subject: R and the Google Summer of Code 2010 -- Please welcome our new st...

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R is going to have a GUI to ggplot2! (by the end of this years google-summer-of-code)

April 26, 2010
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I was delighted to see the following e-mail post from Dirk Eddelbuettel regarding the google-summer-of-code R google group: * * * Earlier today Google finalised student / mentor pairings and allocations for the Google Summer of Code 2010 (GSoC 2010). The R Project is happy to announce that the following students have been accepted: Colin Rundel, “rgeos – an...

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R Project websites down

April 26, 2010
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The main R Project website, www.r-project.org, many of the primary CRAN mirrors (including cran.r-project.org), and r-forge.r-project.org are currently unavailable following a power failure at the master host in Austria. The US CRAN mirror, cran.us.r-project.org, and other mirrors not under the r-project.org domain (including cran.revolution-computing.com) are still accessible. In addition, the following services are not affected: bugs.r-project.org, developer.r-project.org, ess.r-project.org, search.r-project.org,...

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A serial Connection for R

April 26, 2010
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***UPDATED: June 3, 2010 – revert name from “tty” to “serial“, R version (2.11.1)*** I’m working on a patch for R (currently 2.11.1) that adds a serial connection feature for POSIX systems (i.e. Linux, Mac OS X, …). The serial connection works like the other connections. For example, the following code opens, writes a single

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Example 7.34: Propensity scores and causal inference from observational studies

April 26, 2010
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Example 7.34: Propensity scores and causal inference from observational studies

Propensity scores can be used to help make causal interpretation of observational data more plausible, by adjusting for other factors that may responsible for differences between groups. Heuristically, we estimate the probability of exposure, rather t...

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R : NA vs. NULL

April 25, 2010
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R : NA vs. NULL

The R language has two closely related NULL-like values, NA and NULL ... Both are used to represent missing or undefined values. This has lead to much confusion.

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Summarising data using box and whisker plots

April 25, 2010
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Summarising data using box and whisker plots

A box and whisker plot is a type of graphical display that can be used to summarise a set of data based on the five number summary of this data. The summary statistics used to create a box and whisker plot are the median of the data, the lower and upper quartiles (25% and 75%)

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How to upgrade R on windows – another strategy (and the R code to do it)

April 23, 2010
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How to upgrade R on windows – another strategy (and the R code to do it)

Update: In the end of the post I added simple step by step instruction on how to move to the new system. I STRONGLY suggest using the code only after you read the entire post. Background If you didn’t hear it by now – R 2.11.0 is out with a bunch of new features. After Andrew Gelman recently lamented the lack...

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Some LaTeX Gems – Part 1: TikZ, Loops and more

April 23, 2010
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Some LaTeX Gems – Part 1: TikZ, Loops and more

This logo means that the blog post is about something I have found interesting, but does not apply directly to the exact purpose of this blog. Note: These commands have been tested in pdflatex. I am not sure if they work in other distributions. Over the past couple of months, I have been assisting with editing some papers and also doing...

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Because it’s Friday: Four chords, and the truth

April 23, 2010
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This one's for the musicians out there. (By the way, in my purely anecdotal experience, musical aptitude appears to have a higher-then-expected representation amongst stats folks. I however am the exception that proves the rule, as anyone who's suffered through my Rock Band vocals can attest. But I digress.) What do the chords C#minor, A, E and B have...

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R/Finance 2010 … and unicorns

April 23, 2010
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At the Information Management blogs, Steve Miller has posted a great roundup of last weekend's R/Finance 2010 conference in Chicago. Here's Steve's overall take: This year's conference was even better than the 2009 inaugural, the in-excess-of-200 participants consumed by more than 20 consecutive high-powered presentations over the fast-paced day and a half. And while I'm a quantitative finance welterweight...

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