Monthly Archives: December 2010

Reproducible Research and R Workflow

December 6, 2010
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Jeromy Anglim discusses best practices and tools used to support reproducible research in R. He discusses tools for R scripting and version control; and provides examples of SWeave.This presentation was given to the Melbourne R Users Group (MelbURN)...

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3 weak days in a row

December 6, 2010
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3 weak days in a row

Recently, Trading the odds posted one of many flavors of mean reverting strategies and I decided to get my hands dirty by writing R code and testing it. You can find full description of the strategy by following latter link above. Long story short – if SPY shows lower open, high and close 3 days in

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JAGS – Bayesian Analysis

December 6, 2010
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JAGS – Bayesian Analysis

JAGS is used for Bayesian analysis using MCMC and stands for Just Another Gibbs Sampler.  It is an alternative to WinBUGS and can be accessed through R just like WinBUGS (via R2jags or RJags).  It will work on a Mac unlike WinBUGS.  The ...

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Using the "Divide by 4 Rule" to Interpret Logistic Regression Coefficients

December 6, 2010
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I was recently reading a bit about logistic regression in a book on hierarchical/multilevel modeling when I first learned about the "divide by 4 rule" for quickly interpreting coefficients in a logistic regression model in terms of the predicted probabilities of the outcome. The idea is pretty simple. The logistic curve (predicted probabilities) is steepest at the center where...

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Example 8.17: Logistic regression via MCMC

December 6, 2010
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Example 8.17: Logistic regression via MCMC

In examples 8.15 and 8.16 we considered Firth logistic regression and exact logistic regression as ways around the problem of separation, often encountered in logistic regression. (Re-cap: Separation happens when all the observations in a category sha...

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Electoral Marimekko Plots

December 6, 2010
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Electoral Marimekko Plots

To be reductive, visual displays of quantitative information might be reasonably categorized on a continuum between “data display” and “statistical graphics.” By statistical graphics, I mean a plot that displays some summary of or relationship amongst several variables, likely having undergone some processing or analysis. This may be as simple as a scatterplot of a … Read more

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Bear hunting

December 6, 2010
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Bear hunting

When were there bear and bull markets in US stocks since 1950? Smoothing While we’d really like to estimate the expected return at each point in time, finding bear markets is ambitious enough.  The plan starts by smoothing the daily returns through time, as in Figure 1. Figure 1: Smoothed returns with a 4 year … Continue reading...

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Forecasting workshop: Switzerland, June 2011

December 6, 2010
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Forecasting workshop: Switzerland, June 2011

I will be running a workshop on Statistical Forecasting: Principles and Practice in Switzerland, 20-22 June 2011. Check out the venue: Waldhotel Doldenhorn, Kandersteg! So if you fancy a trip to the beautiful Swiss Alps next June, read on… Outline Forecasting is required in many situations: deciding whether to build another power generation plant in

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R 2.12.0 and Eclipse with StatET installation

December 5, 2010
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A while back I outlined the setup process for running R under the Eclipse integrated development environment with the help of WalWare.de’s StatET plugin for Eclipse, in Windows 7. This post is an update on that procedure for the newer versions of...

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Bayesian adaptive sampling

December 5, 2010
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Bayesian adaptive sampling

In the continuation of my earlier post on computing evidence, I read a very interesting paper by Merlise Clyde, Joyee Ghosh and Michael Littman, to appear in JCGS. It is called  Bayesian adaptive sampling for variable selection and model averaging. The sound idea at the basis of the paper is that, when one is doing

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