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 ...
Monthly Archives: December 2010
Using the "Divide by 4 Rule" to Interpret Logistic Regression Coefficients
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...
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...
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
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...
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
R 2.12.0 and Eclipse with StatET installation
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...
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 
Rethinking ‘loess’ for Binomial-Response Pitch F/X Strike Zone Maps
So after a long hiatus, I'm back for today. I've been crazy busy with a number of different things--including getting engaged and helping plan out wedding dates and things of that sort--and unfortunately have not kept up here on this blog (or on Fanta...
Pareto plot party!
A Pareto plot is an enhanced bar chart. It comes in useful for deciding which bars in your bar chart are important. To see this, take a look at some made up DVD sales data. set.seed(1234) dvd_names <- c("Toy Tales 3", "The Dusk Saga: Black Out", "Urban Coitus 2", "Dragon Training for Dummies", "Germination", "Fe 
Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).
