# Monthly Archives: November 2011

## Generating PPC Keywords in R – Part 2

November 4, 2011
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In a previous post, I discussed how to generate PPC keywords in R. In this post I will provide another example of how to perform this task. Let’s say that I am a auto insurance company that only operates in the state of Illinois. I’m planing on bidding on keywords in Bing and Google which

## Rdatamarket Tutorial

November 4, 2011
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The good folks at DataMarket have posted a new tutorial on using the rdatamarket package (covered here in August) to easily download public data sets into R for analysis. The tutorial describes how to install the rdatamarket package, how to extract metadata for data sets, and how to download the data themselves into R. The tutorial also illustrates a...

## match vs. %in%

November 4, 2011
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match and %in% are two very commonly-used function in R. So, what's the difference of them?First, how to use them -- (copy from R manual)match returns a vector of the positions of (first) matches of its first argument in its second.%in% is a ...

## Confidence interval for predictions with GLMs

November 4, 2011
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Consider a (simple) Poisson regression . Given a sample where , the goal is to derive a 95% confidence interval for given , where is the prediction. Hence, we want to derive a confidence interval for the prediction, not the potential observation...

## Confidence interval for predictions with GLMs

November 4, 2011
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Consider a (simple) Poisson regression . Given a sample where , the goal is to derive a 95% confidence interval for given , where is the prediction. Hence, we want to derive a confidence interval for the prediction, not the potential observation, i.e. the dot on the graph below > r=glm(dist~speed,data=cars,family=poisson) > P=predict(r,type="response", + newdata=data.frame(speed=seq(-1,35,by=.2))) > plot(cars,xlim=c(0,31),ylim=c(0,170)) > abline(v=30,lty=2)...

## Factor to class-membership matrix

November 4, 2011
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Recently on R-bloggers I found a post from chem-bla-ics blog concerning conversion of factors to integer vectors. At the end it stated a problem of conversion of factor variable to class-membership matrix. In comments several nice solutions were p...

## Help: stemming and stem completion with package tm in R

November 3, 2011
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I came across a problem below when doing stemming and stem completion with package tm in R. Word “mining” was stemmed to “mine” with stemDocument(), and then completed to “miners”with stemCompletion(). However, I prefer to keep “mining” intact. For stemCompletion(), … Continue reading →

## Webinar on Portfolio Rebalancing with R and Sybase

November 3, 2011
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R users in the financial industry may be interested in the following webinar hosted by Revolution Analytics' partner Sybase on November 10: Portfolio Rebalancing Using R and Sybase RAP for Intraday Risk Management With volatility and violent intraday swings becoming the new normal, intraday risk controls are now needed to not only reduce your exposures across multiple asset classes,...

## By: Super Nerdy Cool » Build multiarch R (32 bit and 64 bit) on Debian/Ubuntu

have the 64 bit version of R compiled from source on my Ubuntu laptop. I recently had a need for R based on 32 bit since a package I

## Modern Portfolio Optimization Theory: The idea

November 3, 2011
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We were recently given a lecture (by Dr. Susan Thomas) on Harry Markowitz portfolio optimization theory, and I was really fascinating with the noble laureate's story of how he found it difficult to convince his guide about the importance of h...