Inspired by a recent article on Ockham’s razor, this post shows how a simple set of polyhedral dice can clarify the basic idea underlying Bayes factors (or likelihood ratios).  The ideas may be used in a classroom demonstration, and each of the lessons below could be discovered by the students themselves. Meet the Family Our polyhedral dice are a family…

Klaas Sijtsma is an experienced psychometrician and former rector magnificus of Tilburg University. In “Never waste a good crisis”, Sijtsma discusses academic fraud (and in particular the infamous Stapel case, the fallout of which he had to deal with as dean of the School of Social and Behavioral Sciences at Tilburg University) and questionable research practices (henceforth QRPs). Importantly, Sijtsma…

In the previous post I asked the following question: Here is a test of your Bayesian intuition: Suppose you assign a binomial chance parameter θ a beta(2,2) prior distribution. You anticipate collecting two observations. What is your expected posterior distribution? NB. ChatGPT 3.5, Bard, and the majority of my fellow Bayesians get this wrong. The answer will be revealed in…

Here is a test of your Bayesian intuition: Suppose you assign a binomial chance parameter θ a beta(2,2) prior distribution. You anticipate collecting two observations. What is your expected posterior distribution? NB. ChatGPT 3.5, Bard, and the majority of my fellow Bayesians get this wrong. The answer will be revealed in the next post.

Since 2017, Dora Matzke and I have been teaching the master course “Bayesian Inference for Psychological Science”. Over the years, the syllabus for this course matured into a book (and an accompanying book of answers) titled “Bayesian inference from the ground up: The theory of common sense”. The current plan is to finish the book in the next few months,…

Dear František Bartoš: I’m Xu Rui, an employee of Zhejiang Science and Technology Museum, which is located in Hangzhou, Zhejiang province, China, a city not far from Shanghai. I’m writing this letter to sincerely invite you to attend the 12th “Pineapple Science Award”. We find your research <Fair coins tend to land on the same side they started: Evidence from…

In my research master course “Bayesian Inference for Psychological Science” (co-taught with Dora Matzke), students are asked to specify a beta distribution on the probability θ that I will bake a bacon pancake rather than a standard “vanilla” pancake. So θ is my “bacon proclivity” that students are unsure about. The chapter “The pancake puzzle” from our free course book…

Since 2017, Dora Matzke and I have been teaching the master course “Bayesian Inference for Psychological Science”. Over the years, the syllabus for this course matured into a book (and an accompanying book of answers) titled “Bayesian inference from the ground up: The theory of common sense”. The current plan is to finish the book in the next few months,…