Pareto Distribution

The Pareto distribution, named after the Italian economist Vilfredo Pareto, is a power law probability distribution that coincides with social, scientific, geophysical, actuarial, and many other types of observable phenomena. Outside the field of economics it is at times referred to as the Bradford distribution.
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The standard Pareto distribution has density function (for positive parameter c ):
f(x) = c/xc+1 , 1 x, c > 0
where
c is the shape parameter of the distribution.
Pareto distribution (Animation) 
The animation above shows the Pareto distribution for the shape parameter equal to 1, 2, 3, 4, and 5.