# 2901 search results for "twitter"

## Monty Hall by simulation in R

February 3, 2012
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(Almost) every introductory course in probability introduces conditional probability using the famous Monte Hall problem. In a nutshell, the problem is one of deciding on a best strategy in a simple game. In the game, the contestant is asked to select one of three doors. Behind one of the doors is a great prize (free

## speed of R, C, &tc.

February 2, 2012
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My Paris colleague (and fellow-runner) Aurélien Garivier has produced an interesting comparison of 4 (or 6 if you consider scilab and octave as different from matlab) computer languages in terms of speed for producing the MLE in a hidden Markov model, using EM and the Baum-Welch algorithms. His conclusions are that matlab is a lot

## "R": Plotting the spectra (Gasoline) – 002

February 2, 2012
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"R" has a package called "ChemometricsWithR", where we can get data from different analytical instruments including Near Infrared (NIR).Follow the steps to plot the spectra of a gasoline data set:In this other case we plot the spectra of the NIR shootout 2002: > data(shootout)> wavelengths<-seq(600, 1898,by=2)> mattplot(wavelengths,shootout\$calibrate.1,xlab="wavelength(nm)",ylab="log1/R)")>...

## R Chart featured in Facebook IPO

February 2, 2012
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Page 7 of Facebook's 213-page S-1 filing for their record-breaking IPO includes the following chart, under the headline: "Our Mission: To make the world more open and connected". This chart was created using the R language and Hadoop by Facebook intern Paul Butler. (Thanks to the blog IOER Tools for first noticing the inclusion of the chart.) And speaking...

## tenured research position with ABC skills!

February 2, 2012
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I just received this announcement for the opening of a (tenured/civil servant) position in the national research institute in biostatistics, genetics, and agronomy, INRA: Position opening with profile Approximate inference techniques in complex systems Key activities and required skills: You will develop methodological research in the field of statistical inference for models used in environmental

## Analytic applications are built by data scientists

February 1, 2012
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Ventana Research analyst David Menninger was on the judging panel for the Applications of R in Business contest. In a post on the Ventana research blog, he offers his perspectives on the contest, noting that R, as a statistical package, includes many algorithms for predictive analytics, including regression, clustering, classification, text mining and other techniques. The contest submissions supported...

## "R": Looking at the Data (Gasoline) – 001

February 1, 2012
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As other softwares "R" has nice tools to look to the data before to develop the calibration.Statistics for the "Y" variable (in this case octane number) like Maximun, Minimun,..,standard deviation,...are important:> library(ChemometricsWithR)> data(gasoline)> summary(gasoline\$octane)   Min.  1st Qu.  Median    Mean   3rd Qu.    Max.   83.40   85.88    87.75    87.18   88.45    89.60> sd(gasoline\$octane) 1.530078And of course the Histogram:> hist(gasoline\$octane)

## the birthday problem [X’idated]

February 1, 2012
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The birthday problem (i.e. looking at the distribution of the birthdates in a group of n persons, assuming a uniform distribution of the calendar dates of those birthdates) is always a source of puzzlement ! For instance, here is a recent post on Cross Validated: I have 360 friends on facebook, and, as

## ultimate R recursion

January 31, 2012
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One of my students wrote the following code for his R exam, trying to do accept-reject simulation (of a Rayleigh distribution) and constant approximation at the same time: which I find remarkable if alas doomed to fail! I wonder if there exists a (real as opposed to fantasy) computer language where you could introduce constants

## the Art of R Programming [guest post]

January 30, 2012
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(This post is the preliminary version of a book review by Alessandra Iacobucci, to appear in CHANCE. Enjoy !) As Rob J. Hyndman enthusiastically declares in his blog, “this is a gem of a book”. I would go even further and argue that The Art of R programming is a