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Le Monde [reverse] rank test

April 13, 2010

This is the fourth and hopefuly last post about this puzzle. If I translate the problem proposed by Le Monde, it reads as follows Twenty pupils in the class have different grades that are the integers from 1 to 20. The ten girls in the class are ordered from the best grade to the worst […]

Le Monde rank test (corr’d)

April 7, 2010

Since my first representation of the rank statistic as paired was incorrect, here is the histogram produced by the simulation perm=sample(1:20) saple[t]=sum(abs(sort(perm[1:10])-sort(perm[11:20]))) when . It is obviously much closer to zero than previously. An interesting change is that the regression of the log-mean on produces > lm(log(memean)~log(enn)) Call: lm(formula = log(memean) ~ log(enn)) Coefficients: (Intercept)     […]

Le Monde rank test (cont’d)

April 5, 2010

Following a comment from efrique pointing out that this statistic is called Spearman footrule, I want to clarify the notation in namely (a) that the ranks of and are considered for the whole sample, i.e. instead of being computed separately for the ‘s and the ‘s, and then (b) that the ranks are reordered for […]

Le Monde rank test

April 5, 2010

In the puzzle found in Le Monde of this weekend, the mathematical object behind the silly story is defined as a pseudo-Spearman rank correlation test statistic, where the difference between the ranks of the paired random variables and is in absolute value instead of being squared as in the Spearman rank test statistic. I don’t […]

nested sampling X check

September 18, 2020

Andrew Fowlie, Will Handley and Liangliang Su have recently arXived a new paper on checking the convergence of nested sampling by a uniformity test. The argument goes as follows: if the draw from the prior under the likelihood restriction (at the core of the nested sampling principle) is correctly generated, the rank of the realised […]