Monthly Archives: February 2013

Next Kölner R User Meeting: 6 February 2013

February 5, 2013
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Next Kölner R User Meeting: 6 February 2013

Quick reminder: The next Cologne R user group meeting is scheduled for tomorrow, 6 February 2013. All details and the agenda are available on the KölnRUG Meetup site. Please sign up if you would like to come along. Notes from the last Cologne R user group meeting are available here.Thanks also to...

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Tracking Number of Historical Clusters in DOW 30 and S&P 500

February 4, 2013
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Tracking Number of Historical Clusters in DOW 30 and S&P 500

In the Tracking Number of Historical Clusters post, I looked at how 3 different methods were able to identify clusters across the 10 major asset universe. Today, I want to share the impact of clustering on the larger universe. Below I examined the historical time series of number of clusters in the DOW 30 and

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Visualizing networks in R: arc diagrams and hive plots

February 4, 2013
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Visualizing networks in R: arc diagrams and hive plots

Arc diagrams are an alternate way of representing two-dimensional graphs. Rather than scattering the nodes across the page connected by straight edges, you can instead arrange the nodes along a one-dimensional axis, and replace the straight edges with arcs between the nodes. While an arc diagram might not give as good a sense of the connections between the nodes...

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Convenience Sample, SRS, and Stratified Random Sample Compared

February 4, 2013
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Convenience Sample, SRS, and Stratified Random Sample Compared

In class today we were discussing several types of survey sampling and we split into groups and did a little investigation. We were given a page of 100 rectangles with varying areas and took 3 samples of size 10. Our first was a convenience sample. We...

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Help needed with sample selection biases

February 4, 2013
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We are searching for a graduate student to assist us on a very short assignment about sample selection biases and Heckman Probit models. The help is not needed for estimating the models, but instead for reviewing the scenarios where the use of such models is theoretically appropriate or otherwise. For instance, we are particularly interested in determining if Heck...

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Generating Labels for Supervised Text Classification using CAT and R

February 4, 2013
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Generating Labels for Supervised Text Classification using CAT and R

The explosion in the availability of text has opened new opportunities to exploit text as data for research. As Justin Grimmer and Brandon Stewart discuss in the above paper, there are a number of approaches to reducing human text to … Continue reading →

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Landmine detection revisited; the inverse unicorn problem

February 4, 2013
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Landmine detection revisited; the inverse unicorn problem

A couple weeks ago I wrote about an interesting idea to clear landmines using the power of the wind. A reader asked me to comment more on the value of using these wind-powered “Kafons” to do an initial assay of a suspected minefield, an idea I mentioned at the end of my video on the

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An infelicity with Value at Risk

February 4, 2013
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An infelicity with Value at Risk

More risk does not necessarily mean bigger Value at Risk. Previously “The incoherence of risk coherence” suggested that the failure of Value at Risk (VaR) to be coherent is of little practical importance. Here we look at an attribute that is not a part of the definition of coherence yet is a desirable quality. Thought … Continue reading...

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analyze the survey of income and program participation (sipp) with r

February 4, 2013
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if the census bureau's budget was gutted and only one complex sample survey survived, pray it's the survey of income and program participation (sipp).  it's giant.  it's rich with variables.  it's monthly.  it follows households over three, four, now five year panels.  the congressional budget office uses it for their health insurance simulation.  analysts read that sipp has...

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Data Visualization for Education

February 3, 2013
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Recently I was invited to give a talk to two cohorts of Strategic Data Project fellows. I was asked to speak about using data visualization to help inform decision-making of policy makers. At the same time, the group had a lot of variation in their int...

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