[WikiEN-l] The Statistical Decline of the English Wikipedia Community

[Joseph Reagle]

On Wednesday 10 October 2007, Steven Walling wrote:
> You're trying to make an accurate judgment based on 100k of articles 
> from a 2 million article field? Don't insult our intelligence.

That might insult your intuitions, but not a statistician's intelligence -- 
not that I'm one. If the sampling is random and we can make some standard 
assumptions, a 100K article sample size would be *overkill*, be it a 2 
million or 20 million population.

On October 30, 2006 -- the last day for the WP Report statistics - I believe 
the number of new accounts created was 7940 . If we look at the previous 10 
months the average is 9092 with a std. dev. 608. Robert says he 
notices -25% decrease, so I'm going to assume that's nearly 1985 less 
account creations or 5955 account creations in his sample.

Now then, what's the chance that Robert's value (5955) was simply the result 
of a freakish variation from his sample of a population that was continuing 
as it was, to say nothing of continued massive growth?  (This is what I'm 
inferring you to be claiming.) Impossibly small. See:
  http://en.wikipedia.org/wiki/Statistical_power