## Archive for xkcd

## editor’s nightmare

Posted in Books, Kids, pictures, University life with tags Fermat, Fermat's theorem, fonts, NIPS, proceedings, xkcd on June 24, 2014 by xi'an## a refutation of Johnson’s PNAS paper

Posted in Books, Statistics, University life with tags Alice and Bob, Bayes factor, Bayesian statistics, Bayesian tests, hypothesis testing, p-value, Valen Johnson, xkcd on February 11, 2014 by xi'an**J**ean-Christophe Mourrat recently arXived a paper “P-value tests and publication bias as causes for high rate of non-reproducible scientific results?”, intended as a rebuttal of Val Johnson’s PNAS paper. The arguments therein are not particularly compelling. (Just as ours’ may sound so to the author.)

“We do not discuss the validity of this[Bayesian]hypothesis here, but we explain in the supplementary material that if taken seriously, it leads to incoherent results, and should thus be avoided for practical purposes.”

**T**he refutation is primarily argued as a rejection of the whole Bayesian perspective. (Although we argue Johnson’ perspective is not that Bayesian…) But the argument within the paper is much simpler: if the probability of rejection under the null is at most 5%, then the overall proportion of false positives is also at most 5% and not 20% as argued in Johnson…! Just as simple as this. Unfortunately, the author mixes conditional and unconditional, frequentist and Bayesian probability models. As well as conditioning upon the data and conditioning upon the rejection region… Read at your own risk. Continue reading

## an easy pun on conditional risk[cd]

Posted in Books, Kids, Statistics with tags Bayes theorem, beach, compatible conditional distributions, Laplace succession rule, xkcd on September 22, 2013 by xi'an## the original xkcd entry on Bayes [with its mistake]

Posted in Books, Kids, Statistics with tags Bayes theorem, xkcd on July 13, 2013 by xi'an## Bayes is back on xkcd

Posted in Books, Kids, Statistics with tags Bayes theorem, conditioning, seashells, xkcd on July 12, 2013 by xi'an## moaning for the good olde days

Posted in Kids with tags Internet, olde times, xkcd on June 25, 2013 by xi'an## Bayes on the radio

Posted in Books, pictures, Statistics, University life with tags Bayes theorem, Bayesian statistics, France Culture, frequentist inference, Henri Poincaré, Higgs boson, Nate Silver, physiology, radio, radio show, Science & Vie, Thomas Bayes, xkcd on November 10, 2012 by xi'an**I**n relation with the special issue of Science & Vie on Bayes’ formula, the French national radio (France Culture) organised a round table with Pierre Bessière, senior researcher in physiology at Collège de France, Dirk Zerwas, senior researcher in particle physics in Orsay, and Hervé Poirier, editor of Science & Vie. And myself (as I was quoted in the original paper). While I am not particularly fluent in oral debates, I was interested by participating in this radio experiment, if only to bring some moderation to the hyperbolic tone found in the special issue. (As the theme was “Is there a universal mathematical formula? “, I was for a while confused about the debate, thinking that maybe the previous blogs on Stewart’s *17 Equations* and Mackenzie’s *Universe in Zero Words* had prompted this invitation…)

**A**s it happened [podcast link], the debate was quite moderate and reasonable, we discussed about the genesis, the dark ages, and the resurgimento of Bayesian statistics within statistics, the lack of Bayesian perspectives in the Higgs boson analysis (bemoaned by Tony O’Hagan and Dennis Lindley), and the Bayesian nature of learning in psychology. Although I managed to mention Poincaré’s Bayesian defence of Dreyfus (thanks to the *Theory that would not die*!), Nate Silver‘s Bayesian combination of survey results, and the role of the MRC in the MCMC revolution, I found that the information content of a one-hour show was in the end quite limited, as I would have liked to mention as well the role of Bayesian techniques in population genetic advances, like the Asian beetle invasion mentioned two weeks ago… Overall, an interesting experience, maybe not with a huge impact on the population of listeners, and a confirmation I’d better stick to the written world!