Explanation: Reference group is a term used in research, Experiments or statistical analysis to describe a group of special interest. It can is known as the standard or control group of which other group o groups are to be compared. A reference group can help to explain the upper-class revolunary, renegade Catholics and reactionary union members etc. The reference group concept can be used in all fields of life for any research or Experiment or for comparisons.
Explanation: A reference group is basically a group that is used as a measurement that one can compare another group to.
Any group used as a standard in evaluation of other groups are known as reference group.
The upper class revolutionary, renegade catholic, reactionary union are all examples of groups and they can be used as references to other groups. hence they can be used to explain the behavior of other groups.
A case–control study is a type of observational study in which two existing groups differing in outcome are identified and compared on the basis of some supposed causal attribute
There does not appear to be such a specialty in psychology - ego psychology covers studies in the case of identity and childhood and adolescence psychological development are covered by pediatric psychology.