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More StackExchange sites

July 16, 2010 | Rob J Hyndman

The StackExchange site on Statistical Analysis is about to go into private beta testing. This is your last chance to commit if you want to be part of the private beta testing. Don’t worry if you miss out — it will only be a week before it is then open ...
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Documenting R‘s Connections Internals

July 16, 2010 | Matt Shotwell

In studying R‘s connections source code, I’ve put together a series of notes about their workings. Rather than let the notes go where most of my notes go (I have no idea ), I decided to do some proofreading and make the notes available to others who might be ... [Read more...]

Short Open Source Q&A with Revolution Analytics

July 14, 2010 | Matt Shotwell

I recently e-mailed David Smith of Revolution Analytics with a few questions about their relationship with the R-project, and how they handle R‘s source code. David mentioned, and I’m flattered that my email motivated an additional page on the Revolution website. Beyond this, I have no other relationship ... [Read more...]

Funny Math in Governor Approval Ratings

July 9, 2010 | Matt Shotwell

Andrew Gelman wrote today about some erroneous U.S. Governor approval ratings, noting that the ratings for Janet Napolitano sum to 108%. In fact most of these ratings do not sum to 100%. I prepared a clean CSV file of the ratings, making use of R‘s XML library and the readHTMLTable ... [Read more...]

ASCII Scatterplots in R

June 25, 2010 | Matt Shotwell

I really like R‘s stem function, it creates a stem-and-leaf plot right in the R console, no fancy graphics devices required! In a recent R-help post, Ralf Bierig presented a very nice ASCII scatterplot representing two densities. Unfortunately, I don’t know of any R function that will generate ... [Read more...]

Dynamic Modeling 2: Our First Substantive Model

May 30, 2010 | Tony

(This is the second of a series of ongoing posts on using Graph Algebra in the Social Sciences.) First-order linear difference equations are powerful, yet simple modeling tools.  They can provide access to useful substantive insights to real-world phenomena.  They can have powerful predictive ability when used appropriately.  Additionally, they ... [Read more...]

Chicago R Meetup: Healthier than Drinking Alone

May 24, 2010 | JD Long

I’m kinda blown away by the number of folks who have joined the Chicago R User Group (RUG) in the last few weeks. As of this morning we have 65 people signed up for the group and 25 who have said that they are planning on attending the meetup this Thursday (...
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The only thing smiling today is Volatility

May 21, 2010 | Lee

With the stock market freaking out and all, I figured I should take a look at how volatility was being priced in the option market. The CBOE generously provides snapshots of market data for anyone interested to download. By using this data, we can calculate the markets ‘implied volatility’, or ...
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Basket Option Pricing: Step by Step

May 8, 2010 | Lee

I find options fascinating because they deal with the abstract ideas of volatility and correlation, both of which are unobservable and can often seem like wild animal spirits (take the current stock market as an example). Understanding these subtle concepts is never easy, but it is essential in pricing some ... [Read more...]

Virtual Conference: R the Language

May 3, 2010 | JD Long

On Tuesday May 4th at 9:30 PM central, 10:30 eastern, I’ll be giving a live online presentation as part of the Vconf.org open conference series. I’ll be speaking about R and why I started using R a couple years ago. This is NOT going to be a technical presentation ...
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5 Minute Analysis in R: Case-Shiller Indices

April 29, 2010 | Lee

The Case-Shiller Home Price Indices measure residential home values for 20 cities in the US, with some indices going all the way back to the 80s. With housing prices all the rage these days, we should perform a quick-and-dirty analysis using R to see what we can glean from this rich ...
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Fun with the Vasicek Interest Rate Model

April 22, 2010 | Lee

A common model used in the financial industry for modelling the short rate (think overnight rate, but actually an infinitesimally short amount of time) is the Vasicek model. Although it is unlikely to perfectly fit the yield curve, it has some nice properties that make it a good model to ... [Read more...]

Simulating Dart Throws in R

April 16, 2010 | JD Long

Back in November 2009 Wired wrote an article about some grad students who decided to try to stochastically model throwing darts. Because I don’t actually read printed material I didn’t see the article until a couple of months ago. My immediate thought was, “hey, I drink beer. I throw ... [Read more...]

R Command Line

April 16, 2010 | Lee

I am an R user! And I see a whole army of R users, here in defiance of tyranny. You’ve come to use R as free men… and free men you are. What will you do with that freedom? Will you use R? Use R and you may use ...
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Anecdotal Evidence that Facebook Stores all Clicks?

April 11, 2010 | Ryan

This is not really news. A few months ago, news broke that Facebook recorded each user’s clicks and profile views in a database. Of course, I am not at all surprised. I would be more surprised if they didn’t store every single click. By now, most people have ... [Read more...]

The Future of Math is Statistics

April 9, 2010 | JD Long

The future of math is statistics… and the language of that future is R: I’ve often thought there was way too little “statistical intuition” in the workplace. I think Author Benjamin would agree. [Read more...]
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