24 Sep 2003
CS 6210 – Module 6
6
Zipf-Yule-Pareto Law
‘Pn ≈ 1/na
l where Pn is the frequency of occurrence of the nth ranked item, and a is some constant.
‘
‘“The probability of occurrence of a value of some variable starts high and tapers off. Thus, a few values occur very often while many others occur rarely.”
‘
‘Pareto – for land ownership in the 1800’s
‘Zipf – for word frequency
‘Also known as the 80/20 rule and as Zipf-Mandelbrot
‘Used to measure of citings per paper:
‘ # of papers cited n times is about 1/na of those being cited once, where a ≈ ____