Ahistorian is studying urban history in chicago in the early 1900s. she is studying the population changes and the activities that people did in their everyday lives. based on this description, which school of thought does the historian likely belong to?

It would most likely be a social school of thought. 
She is focusing on a group of normal people and there everyday lives.

"Social thought is a philosophical and intellectual ideas of a person or persons regarding to a particular time, place and about the growth, development and decay of human societies. Social thought is a current social thinking about the structure and functions of a social system."

^^^ i agree with the person above me, good luck on whatever : )