Another graph showing the recent peak in daily deaths throughout France as recorded by INSEE and plotted by Baptiste Coulmont from Paris 8 Sociology Department. And further discussed by Arthur Charpentier on Freakonometrics. With a few days off due to reporting, this brings an objective perspective on the impact of the ...

A weekly Monde current mathematical puzzle that reminded me of an earlier one (but was too lazy to check): The integer n=36 enjoys the property that all the differences between its ordered divisors are also divisors of 36. Find the only 18≤m≤100 that enjoys this property such that all its prime ...

This book was sent to me by CRC Press for review for CHANCE. I read it over a few mornings while [confined] at home and found it much more computational than statistical. In the sense that the authors go quite thoroughly into the construction of standard learning procedures, including home-made ...

One version of the wrapped Normal distribution on (0,1) is expressed as a sum of Normal distributions with means shifted by all relative integers which, while a parameterised density, has imho no particular statistical appeal over the use of other series. It was nonetheless the centre of a series of questions ...

A weekly Monde current mathematical puzzle that reminded me of an earlier one (but was too lazy to check): If ADULE-ELUDE=POINT, was is the largest possible value of POINT? With the convention that all letters correspond to different digits and no digit can start with 0. Same question when ADULE+...

Probability and Bayesian modeling is a textbook by Jim Albert and Jingchen Hu that CRC Press sent me for review in CHANCE. (The book is also freely available in bookdown format.) The level of the textbook is definitely most introductory as it dedicates its first half on probability concepts (with ...

A weekly Monde current mathematical puzzle on gcd’s and scm’s: If one replaces a pair (a,b) of integers with the pair (g,s) of their greatest common denominator and smallest common multiple, how long at most before the sequence ends. Same question when considering a collection of ...

Most regrettably, the incoming ABC in Grenoble, planned on 19-20 March 2020 is now postponed till a yet unspecified date, like next Summer or next Fall. Due to travel disruptions all over the World and to gathering restrictions in France, courtesy of the Covid-19 virus. Not particularly surprising given the avalanche ...

A paper (and an introduction to the paper) in Nature this week seems to have made progress on the existence of indefinite predator-prey cyles. As in the lynx/hare dataset available on R. The paper is focusing on another pair, an invertebrate and its prey, an algae. For which the ...

A vaguely arithmetic challenge as Le weekly Monde current mathematical puzzle: Given two boxes containing x and 2N+1-x balls respectively. If one proceeds by repeatedly transferring half the balls from the even box to the odd box, what is the largest value of N for which the resulting sequence ...

Two weeks ago, Kurcharski et al., from the CMMID nCoV working group at the London School of Hygiene and Tropical Medicine, published on medrXiv a statistical analysis via a stochastic SEIR model of the evolution of the 2019-2020 nCoV epidemics, with prediction of a peak outbreak by late February in ...

A number challenge as Le weekly Monde current mathematical puzzle: When the three consecutive numbers 110, 111 and 112, they all are multiples of the sum of their digits. Are there 4 consecutive numbers with three digits like this? A contrario, does there exist 17 consecutive numbers with three digits such that they cannot be […]

A two-player game as Le weekly Monde current mathematical puzzle: Abishag and Caleb fill in alternance a row of N boxes in a row by picking one then two then three &tc. consecutive boxes. When a player is unable to find enough consecutive boxes, the player has lost. Who is ...

A quick riddle from the Riddler In a two-person game, Abigail and Zian both choose between a and z. Abigail win one point with probability .9 if they choose (a,a) and with probability 1 if they choose (a,z), and two points with probability .4 if they choose (z,z) and with ...

As I was asked to write a chapter on MCMC methods for an incoming Handbook of Computational Statistics and Data Science, published by Wiley, rather than cautiously declining!, I decided to recycle the answers I wrote on X validated to what I considered to be the most characteristic misunderstandings about ...

A very quick Riddler’s riddle last week with the question Find the (integer) fraction with the smallest (integer) denominator strictly located between 1/2020 and 1/2019. and the brute force resolution for (t in (2020*2019):2021){ a=ceiling(t/2020) if (a*2019

A permutation challenge as Le weekly Monde current mathematical puzzle: When considering all games between 20 teams, of which 3 games have not yet been played, wins bring 3 points, losses 0 points, and draws 1 point (each). If the sum of all points over all teams and all games is 516, was is the […]