Monthly Archives: June 2012

Grouped means (again)

June 26, 2012
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Grouped means (again)

So, the post I did yesterday on aggregate seemed to go down well. One of the comments suggested I add an example. Other comments had other useful hints which I thought I’d pass on more formally. So here goes… The mtcars dataset in base has data on various aspects of cars – miles per gallon,

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How to Convert Rugby into Football/Soccer Scores

June 26, 2012
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How to Convert Rugby into Football/Soccer Scores

Following the Irish rugby team’s humiliating 60-0 defeat to New Zealand, an interesting question was posed on Twitter: what does a 60-0 result convert to in football/soccer? Intrigued, I decided to gather some data from both the English premier league (this season, more data collected and future blog posts to come!) and the equivalent English

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Shading regions of the normal: The Stanine scale

June 26, 2012
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Shading regions of the normal: The Stanine scale

For the presentation of norm values, often stanines are used (standard nine). These values mark a person’s relativ position in comparison to the sample or to norm values. According to Wikipedia: The underlying basis for obtaining stanines is that a normal distribution is divided into nine intervals, each of which has a width of 0.5

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Bayesian Nonparametrics in R

June 25, 2012
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Bayesian Nonparametrics in R

On July 25th, I’ll be presenting at the Seattle R Meetup about implementing Bayesian nonparametrics in R. If you’re not sure what Bayesian nonparametric methods are, they’re a family of methods that allow you to fit traditional statistical models, such as mixture models or latent factor models, without having to fully specify the number of

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Strategy Diversification in R – follow up

June 25, 2012
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Strategy Diversification in R – follow up

The strategies used in Strategy Diversification in R were labeled as Strategy1 and Strategy2. Strategy1 Indicator: 52 week Simple Moving Average Entry Rule: Buy 1000 shares when price crosses and closes above 52 week Simple Moving Average Exit Rule: Exit all positions when prices crosses and closes below 52 week Simple Moving Average Classification: Long … Continue reading...

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Rcpp 0.9.12

June 25, 2012
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A bug-fix release 0.9.12 of Rcpp arrived earlier today on CRAN and is now in Debian too.This fixes a minor snafu with the Rcpp::Enviroment constructor following a minor change made for 0.9.11. It also reduces the number of unit tests running by de...

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Wordcloud of the Arizona et al. v. United States opinion

June 25, 2012
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Wordcloud of the Arizona et al. v. United States opinion

Here’s one purely for fun – a wordcloud built from the Supreme Court’s opinion on Arizona et al. v United States.  Word clouds, though certainly not the most scientific of visualization techniques, are often engaging and “fun” ways to lead…Read more ›

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New R User Groups in Ankara, Toronto

June 25, 2012
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Two new local R user groups to report this week. In Turkey, the Ankara R Users Group has just started up. No meetings are scheduled yet, so be sure to suggest a meeting time/location when you sign up. The Toronto-based R Matlab Users group focuses on financial services applications. Created by Bryan Downing (who also produces the QuantLabs blog),...

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Olive Oil NIR/VIS Spectra – 001 (ChemSpec)

June 25, 2012
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Olive Oil NIR/VIS Spectra – 001 (ChemSpec)

I continue with the practicing with ChemSpec, and this time I import seven spectra of olive oil. This time I have been more careful and I have the frequency column as numeric form the CSV file. Once I have the spectra (with and offset):Take in account ...

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Avoid Overplotting of Text in Ordination Diagram

June 25, 2012
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Avoid Overplotting of Text in Ordination Diagram

Referring to a recent posting on r-sig-eco mailing list I'll add this example to theBioBucket:library(vegan)library(vegan)data(dune)sol <- metaMDS(dune) # use ordipointlabel -# here is an example where I added cex according to species frequencies:pl...

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