---------------------------------------- > Date: Fri, 24 May 2013 12:01:35 -0700 > Subject: Re: Simple algorithm question - how to reorder a sequence > economically > From: peter.h.m.bro...@gmail.com > To: python-list@python.org > > On May 24, 5:00 pm, Carlos Nepomuceno <carlosnepomuc...@outlook.com> > wrote: >> >> >> I don't know what "spurious evidence of correlation" is. Can you give a >> mathematical definition? >> > If I run the simulation with the same sequence, then, because event E1 > always comes before event E2, somebody might believe that there is a > causative connection between them in the world that's being simulated, > when, in fact, they only correlate in this way because the sequence is > not being shuffled. That's what it means.
Correlation does not imply causation. If "somebody" is an expert system and you want to avoid it's recognition and/or triggering of some kind, and you can't or don't want to change it's behavior, you may take the random way because it's cheaper. > Actually it'll be a bit more subtle than that, because each iteration > of the simulation updates all nodes in one time interval, the events > will not usually show the order of iteration - but, where there are > any secondary effects, that are related to the order in which the > nodes are updated, these will always happen the same way, which is my > concern. You should have a more precise understanding of the dependence of the variables you taking in consideration before randomizing the series of events your are using for tests. I suggest you start using PPMCC. If it's close to zero or negative you wouldn't have to mind about it! ;) -- http://mail.python.org/mailman/listinfo/python-list
