There is an example of this in the documentation for ParetoDistribution under the "Scope" section:
http://reference.wolfram.com/language/ref/ParetoDistribution.html
(* Generate Some Random Data *)
sample = RandomVariate[ParetoDistribution[2, 5], 10^3];
(* Use EstimatedDistribution to Find the Most Likely Parameters For ParetoDistribution *)
edist = EstimatedDistribution[sample, ParetoDistribution[k, \[Alpha]]]
(* Compare Them in a Plot *)
Show[Histogram[sample, {2, 6, 0.2}, "PDF"],
Plot[PDF[TruncatedDistribution[{2, 6}, edist], x], {x, 2, 6},
PlotStyle -> Thick, PlotRange -> {0, 2}]]
