1170 search results for "tutorial"

R-Bloggers Steadily Growing

February 15, 2012
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R-Bloggers Steadily Growing

Description: Number of blogs aggregated into the R-Bloggers news site. Data: http://www.r-bloggers.com/ Analysis: R-Bloggers is a website devoted to news and tutorials related to the R programming language. The content is generated by a growing ...

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In case you missed it: January Roundup

February 13, 2012
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In case you missed them, here are some articles from January of particular interest to R users. Sponsorships from Revolution Analytics are now available for local R user groups in 2012. The winners of the Applications of R in Business Contest have been announced. The coefplot package visualizes model coefficients and standard errors in a line chart. Revolution Analytics...

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"R" PLS Package: Multiple Scatter Correction (MSC)

February 12, 2012
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"R" PLS Package: Multiple Scatter Correction  (MSC)

MSC (Multiple Scatter Correction) is a Math treatment to correct the scatter in the spectra. The scatter is produced for different physical circumstances as particle size, packaging.Normally scatter make worse the correlation of the spectra with the constituent of interest.Almost all the chemometric software’s available include this math treatment and of course “R” have it as well in the...

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"R": Predicting a Test Set (Gasoline)

February 9, 2012
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"R": Predicting a Test Set (Gasoline)

> data(gasoline)> #60 spectra of gasoline (octane is the constituent) > #We divide the whole Set into a Train Set and a Test Set.> gasTrain<-gasoline> gasTest<-gasoline> #Let´s develop the PLSR with the Tain Set ...

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"R": PLS Regression (Gasoline) – 005

February 8, 2012
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"R": PLS Regression (Gasoline) – 005

Let´s see know how to plot the scores for the 3 PLS Components:  We can see the explained variance from each component in the diagonal.We can get it from R with:> explvar(gas1)   Comp 1      Comp 2  &nbs...

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"R": PLS Regression (Gasoline) – 004

February 7, 2012
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"R": PLS Regression (Gasoline) – 004

In the previous post we plot the Cross Validation predictions with:> plot(gas1, ncomp = 3, asp = 1, line = TRUE)We can plot the fitted values instead with:> plot(gas1, ncomp = 3, asp = 1, line = TRUE,which=train) Graphics are different:Of course, using "train" we get  overoptimisc statistics and we should look...

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"R": PLS Regression (Gasoline) – 003

February 3, 2012
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"R": PLS Regression  (Gasoline) – 003

The gasoline data set has the spectra of 60 samples acquired by diffuse reflectance from 900 to 1700 nm. We saw how to plot the spectra in the previous post.Now, following the tutorial of Bjorn-Helge Mevik published in "R-News Volume 6/3, August 2006", we will do the PLS regression:gas1 <- plsr(octane~NIR, ncomp = 10,data = gasoline, validation...

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

February 1, 2012
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"R": Looking at the Data (Gasoline) – 001

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)

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Updated Sentiment Analysis and a Word Cloud for Netflix – The R Way!

January 30, 2012
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Updated Sentiment Analysis and a Word Cloud for Netflix – The R Way!

The Netflix investors must be happy and cheerful as the stock is up more than 78% since the beginning of the year (YES, 78%, Source: Yahoo Finance!).  I am not going to talk about what turned the stock around after a much talked/hyp...

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useR! 2012: Earlybird Registration for International R Users Conference, Nashville TN 12-15 2012

January 30, 2012
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The 8th international R users conference useR! 2012 will be in Nashville TN USA June 12-15 with a special all-day pre-conference course from Bill Venables on June 11. We have a terrific lineup of half-day tutorials on June 12 and will have invited and contributed presentations of interest to a wide variety of R users. Details may be found...

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