Things I learned at useR!2011

August 25, 2011
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Things I learned at useR!2011

The title says “things” but conferences are mainly about people. Some of it can be serendipitous.  For example, one day I sat next to Jonathan Rougier at lunch because I had a question for him about climate models.  When Jonathan left, I started a conversation with the person on my other side.  That was most … Continue reading...

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Forecasting time series using R

August 24, 2011
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I’ll be giving a talk on Forecasting time series using R for the Melbourne Users of R Network (MelbURN) on Thursday 27 October 2011 at 6pm. I will look at the various facilities for time series forecasting available in R, concentrating on the forecast package. This package implements several automatic methods for forecasting time series

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Modest Modeest for Moving Average

August 24, 2011
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Modest Modeest for Moving Average

I have no idea who originated the idea of using moving averages to determine entry and exit points in a trading system.  I do know that Mebane Faber (briefly discussed in Shorting Mebane Faber) has recently popularized the notion through his >7...

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New R User Group at University of Utah

August 24, 2011
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There's a new local R user group in Salt Lake City, based at the University of Utah. (There used to be another group in Salt Lake devoted to R/Weka/Processing, but it appears to now be defunct.) This new group has been meeting regularly for some time, and their next meeting, on September 9, will be devoted to short talks...

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le logiciel R

August 24, 2011
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le logiciel R

For once, here is a book review I wrote in French about the book Le logiciel R, written by Pierre Lafaye de Micheaux (Université de Montréal), Rémy Drouilhet (Université de Grenoble 2) and Benoît Liquet (Université de Bordeaux 2): Ce livre édité par Springer (dans la même collection que Le Choix Bayesien) propose une couverture

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The Open Governance Index: Results for The R Project

August 24, 2011
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Just over two weeks ago, I invited readers to complete the Open Governance Index (OGI) Questionnaire regarding The R Project. The OGI evaluates several facets of governance in open source projects (OGI publication). The OGI questionnaire is reproduced below, and each question is linked from the table of useR responses. The table below presents the

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Estimating a normal mean with a cauchy prior

August 24, 2011
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Estimating a normal mean with a cauchy prior

The setup When doing statistics the Bayesian way, we are sometimes bombarded with complicated integrals that do not lend themselves to closed-form solutions. This used to be a problem. Nowadays, not so much. This post illustrates how a person can...

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Another Rchievement of the day

August 24, 2011
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Another Rchievement of the day

Time for another Rchievement of the day. This is a neat little example demonstrating the power of control flow (type ?Control in R to find out more). But perhaps a not-so obvious way of using it. So what does this … Continue reading →

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The problem with R? Too much new stuff!

August 23, 2011
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In a tongue-in-cheek post at the Information Management blog, Steve Miller shares his "frustration" with R: package developers keep on releasing new functionality for R that makes his own work obsolete. For example, there's now pre-packaged functionality in R for enhanced dotplots, Economist-style graphics, additive regression models and more, which all obviate the need for Steve to implement such...

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expectation-propagation and ABC

August 23, 2011
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expectation-propagation and ABC

“It seems quite absurd to reject an EP-based approach, if the only alternative is an ABC approach based on summary statistics, which introduces a bias which seems both larger (according to our numerical examples) and more arbitrary, in the sense that in real-world applications one has little intuition and even less mathematical guidance on to

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Data manipulations

August 23, 2011
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In the last Utah R Users group meeting I gave a presentation on data manipulations on R, and today I found through the plyr mailing list two commands that I was previously unaware of that should definitely be made mention of, arrage and mutate.

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Z-Tests: Should we even bother?

August 23, 2011
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Z-Tests: Should we even bother?

Should statistical teachers continue to teach z-tests?vote:  save z-test, or stop z-testLooking at textbooks, articles and general research I cannot remember the last time I saw someone use a z-test in a study. I have seen many a t-test, ANOVA, ch...

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Graphically analyzing variable interactions in R

August 23, 2011
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Graphically analyzing variable interactions in R

I studied Ecology as an undergraduate, which meant I spent a lot of time gathering and analyzing field data. One of the basic tools we used to look for relationships in a large set of variables was correlation and scatterplot matrices. Each of these ...

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Accelerating path-dependent loops: A quick Rcpp case study

August 23, 2011
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User BobH asked on StackOverflow about accelerating path-dependent loops. He provided a simple example in which a vector gets filled conditional on the value of the preceding element. Simple to code, but hard to vectorise. By the time I saw that q...

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Anonymising data

August 23, 2011
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Anonymising data

There are only three known jokes about statistics in the whole universe, so to complete the trilogy (see here and here for the other two), listen up: Three statisticians are on a train journey to a conference, and they get chatting to three epidemiologists who are also going to the same place. The epidemiologists are

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Time Series Analysis and Mining with R

August 23, 2011
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Time Series Analysis and Mining with R

Time series data are widely seen in analytics. Some examples are stock indexes/prices, currency exchange rates and electrocardiogram (ECG). Traditional time series analysis focuses on smoothing, decomposition and forecasting, and there are many R functions and packages available for those … Continue reading →

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Random input software testing

August 23, 2011
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Random input software testing

The usual approach to testing software is to create a specific problem and see if the software gets the correct answer.  Although this is very useful, there are problems with it: It is labor-intensive It almost totally neglects to test the code that throws errors There can be unconscious bias in the test cases created … Continue reading...

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Experiences with using SAS and R in insurance and banking

August 23, 2011
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Experiences with using SAS and R in insurance and banking

In July 2011, Hong Ooi presented an engaging talk to Melbourne R Users Group. Both David Smith from Revolutions and Eugene Dubossarsky behind the Analyst First movement have discussed the presentation. The video of the talk is now available for … Continue reading →

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Experiences with using SAS and R in insurance and banking

August 23, 2011
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Hong Ooi talks about some of the more interesting projects that he has used R for in the last year. These include fitting models for mortgage loss given default, a Monte Carlo application for stress-testing loan portfolios (in combination with Excel an...

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A warning on the R save format

August 23, 2011
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A warning on the R save format

The save() function in the R platform for statistical computing is very convenient and I suspect many of us use it a lot. But I was recently bitten by a “feature” of the format which meant I could not recover my data. I recommend that you save data in a data format (e.g. CSV or CDF), not using...

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A warning on the R save format

August 23, 2011
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A warning on the R save format

The save() function in the R platform for statistical computing is very convenient and I suspect many of us use it a lot. But I was recently bitten by a “feature” of the format which meant I could not recover my data. I recommend that you save data in a data format (e.g. CSV or CDF), not using...

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Maiden voyage

August 23, 2011
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Maiden voyage

Who Me. I'm an associate professor of Statistics at Youngstown State University in Youngstown, Ohio, USA. I've been using R for about 7 years, Emacs about 3 years, git about 1 year, and Org-Mode for less than a year. What I want this blo...

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Subjugation to the Sigmas

August 23, 2011
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Subjugation to the Sigmas

No doubt you've heard about the tyranny of the 9s in reference to computer system availability. You're probably also familiar with the phrase six sigma, either in the context of manufacturing process quality control or the improvement of business processes. As we discovered in the recent Guerrilla Data Analysis Techniques class, the two concepts are related.

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Popular topics at the BioStar Q&A site

August 23, 2011
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Popular topics at the BioStar Q&A site

Which topics are the most popular at the BioStar bioinformatics Q&A site? One source of data is the tags used for questions. Tags are somewhat arbitrary of course, but fortunately BioStar has quite an active community, so “bad” tags are usually edited to improve them. Hint: if your question is “How to find SNPs”, then

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Drawdown Visualization

August 22, 2011
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Drawdown Visualization

Drawdown is my favorite measure of risk.  It picks up extended autocorrelated pain often not seen in risk measures, and best illustrates frustration, panic, and loss of confidence (Drawdown Control Can Also Determine Ending Wealth).  I though...

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More useR! 2011 roundups

August 22, 2011
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If you missed last week's worldwide R user conference at the University of Warwick, several attendees have posted informative roundups of the event. Check out these posts from Patrick Burns, Karl Broman, Colin Gillespie, Pairach Piboonrungroj and Richie Cotton (which features a rare, good Statistics joke). My own roundup of the conference was posted on Friday, in case you...

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Webinar Wednesday Aug 24: Revolution R Enterprise, 100% R and More

August 22, 2011
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A heads-up that I'll be giving a free webinar this Wednesday, August 24. In 30 minutes, I'll give an overview of the open-source R project and the additional features of Revolution R Enterprise: R users already know why the R language is the lingua franca of statisticians today: because it's the most powerful statistical language in the world. Revolution...

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Bayesian analysis: Comparing algorithms Part 1?

August 22, 2011
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Bayesian analysis: Comparing algorithms Part 1?

I recently had the opportunity to engage in some Bayesian analysis at work. I was able to state the problem in terms of the lognormal distribution, and took advantage of JAGS and its integration with "R" using the R2jags package. The client was very ha...

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Tenure track position in systematics at the University of Vermont

August 22, 2011
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Tenure track position in systematics at the University of Vermont

There is an awesome position opening up for an assistant professor in systematics at the University of Vermont. Below is the announcement, and see the original post at the Distributed Ecology blog. Why is this related to R? One can do a lot of systemat...

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