In “Fitting Distributions with R” Vito Ricci writes;
“Fitting distributions consists in finding a mathematical function which represents in a good way a statistical variable. A statistician often is facing with this problem: he has some observations of a quantitative character and he wishes to test if those observations, being a sample of an unknown population, belong from a...

Zero Inflated Models and Generalized Linear Mixed Models with R.
Zuur, Saveliev, Ieno (2012).