On 1 December 2014 at 20:55, Stephen John Smoogen <smooge@xxxxxxxxx> wrote: > > > On 1 December 2014 at 05:05, Reindl Harald <h.reindl@xxxxxxxxxxxxx> wrote: >> >> >> Am 01.12.2014 um 12:57 schrieb Pierre-Yves Chibon: >>> So we come back to the question: is any number better than no number at >>> all? >>> Even to get a trend? >> >> >> no number is in fact better than wrong numbers backed by nothing beause >> they lead in wrong conclusions - your 122/133 numbers could in reality also >> be 1000 users installed them from mirrors and your calculation is the best >> example for wrong assumptions >> > > While that is 'true', most of the world doesn't work on 'true'. Your cars > speedometer doesn't give you the accurate km/hour. [Even BMW digital has a > +/- 2 km/hour due to all the factors from tire present size to road > conditions.]. The answer is can you accurately remove enough noise to feel > confident that you are doing 100 km/hour versus 120 km/hour. The same goes > for measuring downloads. > It depends how and why you are collecting data. If, for example, you are sensitive to how often downloads occur from mirrors, then sites that use local repositories will be under-represented. And if that happens to be a use type that typically customises their package choices in some way then those choices wont turn up. There are two types of error in general, random noise and bias. Rough analogy, if your spedometer actually reported 0.85 of your real speed if may not make a very noticeable difference at 30mph, but at 70 it does (and worse if it turns out to be non-linear). -- imalone http://ibmalone.blogspot.co.uk -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct
