In thermodynamics, statistical thermodynamics (or statistical mechanics or statistical physics) is the study of the average energy behaviors of large groups of individual particles.  Statistical thermodynamics can also be defined as the study of the random motion of molecules by means of statistical methods. 
The term "statistical thermodynamics" doesn't seem to have come into use until the 1930s, loosely defined as statistical mechanics with more focus on thermodynamics.
See main: Human physicsMany authors, in recent years, e.g. those in social physics, have used statistical thermodynamics, such as through the guise of a human particle logic, as a basis to argue or explain various bulk human system behaviors, such as distributions of wealth.