Three friends –Alex, Bart, and Cedric– each assign their own prior distribution to a binomial chance parameter θ. Let’s say that θ is the chance that Harriet bakes a vegan pancake rather than a bacon pancake. Alex assigns θ a beta(300,3) prior distribution, indicating a strong belief in high values of θ (i.e., Alex predicts that almost all of Harriet’s…
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Bayes’ rule dictates how new data update the credibility of competing accounts of the world . An immediate consequence of the definition of conditional probability, Bayes’ rule is usually presented as follows: The way I mentally check this equation is to take the denominator of the expression on the right-hand side, , and multiply it with the left side of…
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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,…
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Mounted on a bridge across the river Rubicon, the bust of Julius Caesar eyes the Adriatic sea. Caesar’s nose is shiny, perhaps (but his is speculative, based on limited observations) because passersby feel tempted to touch it with their index finger. A high resolution version is available here (CC-BY). Photo taken by Eric-Jan Wagenmakers, August 4, 2024. In 49 BC,…
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The picture of the Texas sharpshooter is available in our artwork library (CC-BY). Artwork by Dirk-Jan Hoek, concept by Eric-Jan Wagenmakers. In a 2018 blog post I mentioned that it is unclear who first came up with analogy of the Texas sharpshooter: The infamous Texas sharpshooter fires randomly at a barn door and then paints the targets around the bullet…
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The hit series “Clarkson’s Farm” has Jeremy Clarkson attempt farming, in a highly amusing mix between Mr. Bean, John Cleese in Clockwise, and Pat & Mat. After binge-watching the first three seasons, I was struck by one particular topic: the mass death of the piglets. Clarkson houses his sows in “pigloos” — dome-shaped pig farrowing pens. The first time the…
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TLDR; the video is here. This week the Psychological Methods Lab received an 800,000 euro Ammodo Science Award for groundbreaking research. This award was for our entire Psychological Methods group and allows us to develop our joint Open Science research agenda. The logistics was handled expertly by the Ammodo team, from start to finish. Part of the procedure was a…
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This week I came across an inspired/inspiring article by Jim Berger, “Learning statistics from counterexamples“. This short paper strikes at the very heart of statistics; it seems to me that every statistician (whether young or old, frequentist or Bayesian) ought to have an opinion on the counterexamples — sitting on the fence is not an option. Below I give the…
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