order, order!
A very standard (one-line) question on X validated, namely whether min(X,Y) could enjoy a finite mean when both X and Y had infinite means [the answer is yes, possibly!] brought a lot of traffic, including an incorrect answer and bringing it to be one of the “Hot Network Questions“, for no clear reason. Beside my half-Cauchy example, some answers pointed out the connection between mean and cdf, as integrated cdf on the negative half-line and integrated complement cdf on the positive half-line, and between mean and quantile function, as
since it nicely expands to
but I remain bemused by the excitement..! (Including the many answers and the lack of involvement of the OP.)
June 9, 2020 at 4:05 pm
Un peu bébête:. Si
est à valeurs entières alors
.
avec indépendance et si

.
Si
alors
June 9, 2020 at 9:43 pm
Effectivement, ça a le mérite de la simplicité!