Answer:
Case study
Step-by-step explanation:
A case study in psychology is defined as the use of a descriptive research approach to gain an in-depth investigation of a person or a group. There are various ways through which case studies can be conducted such as direct-observation, personal interviews, psychometric tests. Case studies are useful in getting detailed information about the person or a group. The chances of error are also high because the experimenter can provide biased information.