About a year ago my former PhD-student Don van Ravenzwaaij challenged me to write a book that explains Bayesian inference to toddlers, using dinosaurs as the main vehicle of exposition. “I don’t think it’s possible”, Don said. In the words of Michael Jordan, “I took that personally”. Over the past year, I have been tweaking the storyline, and Viktor Beekman…

Summary In the popular indoor mall “Hilvertshof”, in the Dutch town of Hilversum, on Monday October 12th, 2020, at about 3 pm, I counted 175 adults wearing a face mask, and 261 adults not wearing a face mask, for a mask wearing percentage of about 40%. Based on this data collection experience, I also offer four conjectures that future research…

This post is a teaser for Sarafoglou, A., Haaf, J. M., Ly, A., Gronau, Q. F., Wagenmakers, E.-J., & Marsman, M. (2020). Evaluating multinomial order restrictions with bridge sampling. Preprint available on PsyArXiv: https://psyarxiv./bux7p/ Summary Hypotheses concerning the distribution of multinomial proportions typically entail exact equality constraints that can be evaluated using standard tests. Whenever researchers formulate inequality constrained hypotheses,…

The small plastic dome containing a die in the popular game “Mens Erger Je Niet!” (“Don’t Get So Annoyed!”) causes a bias — the die tends to land on the side opposite to how it started. This was not our initial hypothesis, however… The 106-year old game “Mens Erger Je Niet!” (a German invention) involves players tossing a die and…

To paraphrase Mark Twain: “to someone with a hammer, everything looks like a nail”. And so, having implemented the Bayesian A/B test (Kass & Vaidyanathan, 1992) in R and in JASP (Gronau, Raj, & Wagenmakers, 2019), we have been on a mission to apply the methodology to various clinical trials. In contrast to most psychology experiments, lives are actually on…

Sir Ronald Aylmer Fisher (1890-1962) was one of the greatest statisticians of all time. However, Fisher was also stubborn, belligerent, and a eugenicist. When it comes to shocking remarks, one does not need to dig deep: In a dissenting opinion on the 1950 UNESCO report “The race question”, Fisher argued that “Available scientific knowledge provides a firm basis for believing…

This post is a teaser for Maier, Bartoš, & Wagenmakers (2020). Robust Bayesian meta-analysis: Addressing publication bias with model-averaging. Preprint available on PsyArXiv: https://psyarxiv.com/u4cns   Abstract “Meta-analysis is an important quantitative tool for cumulative science, but its application is frustrated by publication bias. In order to test and adjust for publication bias, we extend model-averaged Bayesian meta-analysis with selection models.…

De Finetti’s Representation Theorem is among the most celebrated results in Bayesian statistics. As I mentioned in an earlier post, I have never really understood its significance. A host of excellent writers have all tried to explain why the result is so important [e.g., Lindley (2006, pp. 107-109), Diaconis & Skyrms (2018, pp. 122-125), and the various works by Zabell],…