Google Correlate Certainly Does Not Imply Causation

July 6, 2011
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Google Correlate Certainly Does Not Imply Causation

I recently heard about a new tool called Google Correlate that helps one finds Google search patterns that correspond to (i.e. correlate with) real-world trends.For those that don't get it yet, the tool allows one to type in a search term and the tool ...

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Color reduction of an image – and Warholize?

July 5, 2011
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Color reduction of an image – and Warholize?

There seems to be several methods out there for reducing the colors in an image. I became interested in this after pondering how this is done in the excellent freeware program IrfanView. Unfortunately, their method is not described anywhere that I coul...

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ARMA Models for Trading, Part VI

July 5, 2011
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ARMA Models for Trading, Part VI

All posts in this series were combined into a single, extended tutorial and posted on my new blog. In the fourth posting in this series, we saw the performance comparison between the ARMA strategy and buy-and-hold over the last approximately 10 years. Over the last few weeks (it does take time, believe me) I back-tested

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Even faster linear model fits with R using RcppEigen

Linear regression models are a major component of every applied researcher's toolbox. Obtaining results more quickly is therefore of central importance, particularly when many such models have to be fit. Common examples in this context are Monte Carl...

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A Quantstrat to Build On Part 6

July 5, 2011
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A Quantstrat to Build On Part 6

THIS IS NOT INVESTMENT ADVICE.  ACTING ON THIS MAY LOSE LOTS OF MONEY. In A Quantstrat to Build on Part 5, I promised some performance reporting on quantstrat portfolios, but then in REIT Momentum in Quantstrat, I discovered it is not nearly as ea...

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New R User Group in Argentina

July 5, 2011
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A new local R user group has formed in Buenos Aires, Argentina, under the succinct name ".aR". They're currently putting together the agenda for their first meeting, and are looking for speakers with expertise in the BioConductor project and Finance. If you'd like to join the group, check out the Spanish-language website for .aR, or follow @ar_usergroup on Twitter....

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Sentiment Analysis for Airlines via Twitter

July 5, 2011
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Sentiment Analysis for Airlines via Twitter

Last weekend here in the states was the 4th of July long weekend, one of the busier air travel days of the year. As anyone who flies in the States knows, with air travel often comes frustration, and in this social media age many express their frustration on Twitter: The image above comes from a tutorial on text mining...

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Example 9.1: Scatterplots with binning for large datasets

July 5, 2011
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Example 9.1: Scatterplots with binning for large datasets

Scatterplots can get very hard to interpret when displaying large datasets, as points inevitably overplot and can't be individually discerned. A number of approaches have been crafted to help with this problem. One approach uses binning. This approa...

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Another way to use R in Excel for .NET programmer

July 5, 2011
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Another way to use R in Excel for .NET programmer

As you know, RExcel give us a way to combine R with Excel.But, It just bothering to install some COMs and maybe not be programming but excel manipulation!If you are a .NET programmer, there is another way to call R from Excel.I would like to ...

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Different goals, different looks: Infovis and the Chris Rock effect

July 5, 2011
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Different goals, different looks:  Infovis and the Chris Rock effect

Seth writes: Here’s my candidate for bad graphic of the year: I studied it and learned nothing. I have no idea how they assigned colors to locations. I already knew that there were more within-city calls than calls to individual distant locations — for example that there are more SF-SF calls than SF-LA calls.

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In 4 Steps your Application (including R) is running on a Cloud Computing Cluster

In 4 Steps your Application (including R) is running on a Cloud Computing Cluster

Today, cloud computing is used in many application areas from academic research to industry. Commercial cloud providers as Amazon Web Services (AWS) advertise the simple and fast access to cloud computing resources. Posts in different blogs proof that you can get your application running in the cloud, but it will cost you more than 15

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Bounded target support

July 4, 2011
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Bounded target support

Here is an interesting question from Tomàs that echoes a lot of related emails: I’m turning to you for advice. I’m facing problem  where parameter space is bounded, e.g. all parameters have to be positive. If in MCMC as proposal distribution I use normal distribution, then at some iterations I get negative proposals. So my

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slides from my R tutorial on Twitter text mining #rstats

July 4, 2011
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slides from my R tutorial on Twitter text mining #rstats

Update: An expanded version of this tutorial will appear in the new Elsevier book Practical Text Mining and Statistical Analysis for Non-structured Text Data Applications by Gary Miner et. al which is now available for pre-order from Amazon. In conjunction with the book, I have cleaned up the tutorial code and published it on github.

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R.NET

July 4, 2011
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The R.NET project provides a mechanism for communicating with R from a .NET application. This appears to be a promising way to create simple interfaces to some of the functionality of R. Some examples of using R.NET can be found here and here.

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Contributions to the R Project

July 4, 2011
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The R Project would not exist without the contributions of the R Core Group, the 21 volunteer statisticians and computer scientists from around the world who have donated their time and expertise to create the R langauge, its core packages, and manage its regular release and binary distribution process via the CRAN network. Many Core Group members also tirelessly...

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Questions about quantum computing

July 4, 2011
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I read this article by Rivka Galchen on quantum computing. Much of the article was about an eccentric scientist in his fifties named David Deutch. I’m sure the guy is brilliant but I wasn’t particularly interested in his not particularly interesting life story (apparently he’s thin and lives in Oxford). There was a brief description

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Reverse Iteration

July 3, 2011
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Reverse Iteration

Time to horrify some people.First let's include the code we wrote last time,> source("pretend.R")and the dependency-tracking environment it creates will be used to run all the following examples.Let's look at, I don't know, I'm just trying to demonstrate a language feature so uh... band-pass filtering Gaussian noise.Here's some noise:

Testing for valid variable names

July 3, 2011
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Testing for valid variable names

I have something a fondness for ridiculous variable names, so it’s useful to be able to check whether my latest concoction is legitimate. More so if it is automatically generated. Not having an is_valid_variable_name function is one of those odd omissions from R, and the assign function doesn’t check validity. To recap, there are a

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Best graph ever

July 3, 2011
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Best graph ever

Best graph ever. LARGEST EVER DIFFERENCE BETWEEN 328 and 327 SPOTTED IN NEW YORK CITY

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Learning SAS

July 3, 2011
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Learning SAS

I want to learn the heavy-weight of Statistical softwares - SAS. It seems like the default choice for high-end statistics and I want to understand why.I'm working in the healthcare practice in our firm and want to analyze claims and credit data (Teraby...

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R performance optimization

July 3, 2011
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The blog The Average Investors Blog R posted a nice report about accelerating a default Debian R installation and added some details about his benchmarks in the comment section

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Experimental reasoning in social science

July 2, 2011
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As a statistician, I was trained to think of randomized experimentation as representing the gold standard of knowledge in the social sciences, and, despite having seen occasional arguments to the contrary, I still hold that view, expressed pithily by Box, Hunter, and Hunter (1978) that “To find out what happens when you change something, it

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GIS on a shoestring – Getting traveltimes from google

July 2, 2011
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The analysis of geospatial information is currently a big trend in medicine and public health. Even though some may want to convince you that this can only be achieved with the latest and most expensive software, I am not convinced. First, analysis  of spatial data dates back to at least 1856 when John Snow investigated

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The R apply function – a tutorial with examples

July 2, 2011
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Today I had one of those special moments that is uniquely associated with R. One of my colleagues was trying to solve what I term an 'Excel problem'. That is, one where the problem magically disappears once a programming language is employed. Put simpl...

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My own programming style convention for most languages

July 1, 2011
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I write code mainly in R, and from times to times, in C, C++, SAS, bash, python, and perl. There are style guides out there that help make your code more consistent and readable to yourself and others. Here is a style guide for C++, and here is Google’s style guide for R and here... Read more »

Wikipedia for Kaggle Participants

July 1, 2011
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Kaggle has released a new data-mining challenge: use data from 10 years of Wikipedia edits in order to predict future edit rates. The dataset has been anonymized in order to obscure editor identity and article identity, simultaneously adding focus to the challenge and robbing the dataset of considerable richness. I have some experience with wikipedia…

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B*tchin’ six dimensional 6-cube. The rainbow colours and…

July 1, 2011
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B*tchin’ six dimensional 6-cube. The rainbow colours and…

B*tchin’ six dimensional 6-cube. The rainbow colours and glass panes really help this visualisation.  Examples of 6-dimensional things If it’s hard to envision 6 dimensions, consider this: the possible tunings of a guitar constitute a 6-dimensio...

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B*tchin’ six dimensional 6-cube. The rainbow colours and…

July 1, 2011
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B*tchin’ six dimensional 6-cube. The rainbow colours and…

B*tchin’ six dimensional 6-cube. The rainbow colours and glass panes really help this visualisation.  Examples of 6-dimensional things If it’s hard to envision 6 dimensions, consider this: the possible tunings of a guitar constitute a 6-dimensio...

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How to find R experts on LinkedIn

July 1, 2011
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If you're looking for connections with expertise in R programming, the new Skills and Expertise feature on LinkedIn makes it easy. Just visit the R Skills page for a list of R practitioners on LinkedIn. You can also add "R" to your own list of skills from the same page. You also might want to consider joining the R...

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