mathematics

Simple and heuristic optimization

June 29, 2012 | arthur charpentier

This week, at the Rmetrics conference, there has been an interesting discussion about heuristic optimization. The starting point was simple: in complex optimization problems (here we mean with a lot of local maxima, for instance), we do not ne... [Read more...]

How to outrun a crashing alien spaceship

June 11, 2012 | John Mount

Hollywood movies are obsessed with outrunning explosions and outrunning crashing alien spaceships. For explosions the movies give the optimal (but unusable) solution: run straight away. For crashing alien spaceships they give the same advice, but in this case it is wrong. We demonstrate the correct angle to flee. Running from ... [Read more...]

Playing with fire (or water)

April 2, 2012 | arthur charpentier

A few days ago, http://www.futilitycloset.com/ published a short post based on the fourth problem of the 1987 Canadian Mathematical Olympiad (from on a problem from the 6th All Soviet Union Mathematical Competition in Voronezh, 1966). The problem i... [Read more...]

Even odds

January 22, 2012 | arthur charpentier

This evening, I found a nice probabilistic puzzle on http://www.futilitycloset.com/ "A bag contains 16 billiard balls, some white and some black. You draw two balls at the same time. It is equally likely that the two will be the same color as diff... [Read more...]

Hey! I made you some Wiener processes!

September 7, 2011 | Isomorphismes

Check them out. Here are thirty homoskedastic ones: __ homo.wiener for (j in 1:30) {  for (i in 2:length(homo.wiener)) {          homo.wiener[i,j] for (j in 1:30) {        plot( homo.wiener[,j],           type = "l", col = rgb(.1,.... [Read more...]

The foundations of Statistics [reply]

July 18, 2011 | xi'an

Shravan Vasishth has written a response to my review both published on the Statistics Forum. His response is quite straightforward and honest. In particular, he acknowledges not being a statistician and that he “should spend more time studying statistics”. I also understand the authors’ frustration at trying “to recruit several ... [Read more...]

The foundations of Statistics: a simulation-based approach

July 11, 2011 | xi'an

“We have seen that a perfect correlation is perfectly linear, so an imperfect correlation will be `imperfectly linear’.” page 128 This book has been written by two linguists, Shravan Vasishth and Michael Broe, in order to teach statistics “in  areas that are traditionally not mathematically demanding” at a deeper level than ... [Read more...]

Twitter Math Puzzle and Solution

July 7, 2011 | John Myles White

Yesterday I posted a very simple math puzzle to Twitter that I found in Jonathan Baron’s book, Thinking and Deciding. The puzzle is the following: Show that every number of the form ABC,ABC is divisible by 13. The puzzle comes up in Baron’s book as an example of ... [Read more...]
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