A while back, a friend of mine asked me to help out in a longitudinal project trying to predict cognitive decline in (otherwise healthy) older adults (Mulligan, Areshenkoff, & Smart, 2015). One of the measures we used was resting state … Read more
One can argue the choice of when to stop collecting data should be irrelevant to our choice of parameter estimates, since all information should be contained in the likelihood function. This principle underlies some criticisms of standard hypothesis testing, where … Read more
One major research program in our lab aims to understand how the motor system makes use of task related and perceptual information when planning and executing movement. For example, a right handed “reach and grasp” action is executed more quickly … Read more
This page contains an assortment of useful or informative examples/counterexamples in probability and statistics. I plan to continue updating this page as I come across new examples.
A Bayes factor which contradicts the posterior
The following is an example of … Read more
Edit (05/11/15): The article has been retracted.
Psychological Science recently published a paper — Sadness Impairs Color Perception1 — which has been causing a bit of a ruckus on the statistics blogosphere. Psych Science already has a bit … Read more
More experimenting with the quantile regression model described here. Good regression models are multi-level, so I’ve been playing around at validating a quantile model with random effects.
In the validation of the simple quantile regression model, we … Read more
Most statistical models used in experimental psychology are designed to estimate the mean of a response variable given some set of predictors. This is all well and good when errors are largely symmetric and our predictors are expected to primarily … Read more
It’s difficult to analyze trajectory data, since the “object” of analysis (the trajectory) can’t easily be summarized by a single value without throwing away large amounts of information, unless you already know what you’re looking for (e.g. if you’re looking … Read more
The trend is slowly moving towards interactive plotting and reproducible research with e.g. knitR (which I fully support), but it seems to me that R/ggplot2 is still the best plotting system for static graphics. That said, ggplot’s stock settings … Read more
I’m swimming in reaction time data at the moment. My usual approach to analyzing reaction times in cognitive psychology is through some sort of normal random effects model of the log or inverse RT. This is really only good for … Read more