A psychologist who is interested in finding out about the lives and experiences of blended multi-racial families wants to know how such individuals are viewed by their families, friends, and co-workers and how they view themselves. He conducts a series of structured interviews with the various individuals and asks specific questions based on ideas he has that he thinks will be important for understanding this particular life experience. What type of study is this?

Case study

Explanation:

Case study is defined as the research carried out in deep manner to analyze and understand about any individual, event or situation. This mechanism is carried out through studying the subject in detailed manner, up-closed and structured examination, observing related consideration and facts etc.

According to the question, psychologist is conducting case study for studying about life of multi-racial families by conducting detailed interviews for understanding their life experiences, relation with co-worker, family of friends etc.  

answer; when one group has an extremely high score at pretest;