# Monthly Archives: February 2013

## xts object – subscript out of bounds

February 6, 2013
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I bet you have seen this error a few times. When I compare large xts objects with different number of observations it would hit me right towards the end of the analysis.I wrote a small function, which allows me to check the length of the sets in advanc...

February 5, 2013
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Some little birds had already been whispering about it, but I didn't want to jinx it and told myself I would wait with an announcement until the booksellers have (at least) placeholder pages. And as I learned from Duncan Murdoch via email earlier toda...

## counts numbers in a interval

February 5, 2013
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Say I have a list of values, and I cut them by some break points, how do I know the number of values in each interval?We know cut() function in R works for the purpose.  For example,tx0 <- c(9, 4, 6, 5, 3, 10, 5, 3, 5)x <- rep(0:8, tx0)> ...

## Learning RStudio for R Statistical Computing

February 5, 2013
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"Learning RStudio for R Statistical Computing" will teach you how to quickly and efficiently create and manage statistical analysis projects, import data, develop R scripts, and generate reports and graphics. R developers will learn about package development, coding principles, and … Continue reading →

## Dallas R Users: Learn Shiny this Saturday, 2/9

February 5, 2013
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Just a heads-up for any R users in the Dallas/Fort Worth Metroplex: I’ll be presenting at the Dallas R Users Group this Saturday, 2/9/2013 at 10:00AM at the University of Dallas (1845 East Northgate Drive, Irving, TX). I’ll be talking about how to use RStudio’s new Shiny framework to create R-powered web applications. For the

## Collinearity and stepwise VIF selection

February 5, 2013
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$Collinearity and stepwise VIF selection$

Collinearity, or excessive correlation among explanatory variables, can complicate or prevent the identification of an optimal set of explanatory variables for a statistical model. For example, forward or backward selection of variables could produce inconsistent results, variance partitioning analyses may be unable to identify unique sources of variation, or parameter estimates may include substantial amounts

## Learn about R through data mining

February 5, 2013
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If you're in San Francisco for this week's DeveloperWeek conference, our own Joe Rickert will also giving a presentation on Wednesday at 2:10PM on Predictive Modeling with Big Data in R which will feature several demos of data mining massive data sets using the Revolution R Enterprise. Incidentally, the whole team Revolution Analytics was proud to receive the Top...

## Natura non facit saltus

February 5, 2013
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$\mathbb{E}_{\mathbb{P}}\left(\sum_{i=1}^N Y_i\right)=\mathbb{E}_{\mathbb{P}}(N) \cdot \mathbb{E}_{\mathbb{P}}(Y_i)$

(see John Wilkins’ article on the – interesting – history of that phrase http://scienceblogs.com/evolvingthoughts/…). We will see, this week in class, several smoothing techniques, for insurance ratemaking. As a starting point, assume that we do not want to use segmentation techniques: everyone will pay exactly the same price. no segmentation of the premium And that price should be related to...

## Relearn boxplot and label the outliers

February 5, 2013
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Despite the fact that box plot is used almost every where and taught at undergraduate statistic classes, I recently had to re-learn the box plot in order to know how to label the outliers.This stackoverflow post was where I found how...

## New Rcpp page on upcoming events — including Master Class in New York

February 5, 2013
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Lots of exciting things are happening with and around Rcpp. I just added a new page about Upcoming Events to the recently-created Rcpp site. This events page has lots to cover: an upcoming talk at Columbia on March 8 (details still TBD), a day-lon...