Explanation: Observational study as used in social sciences, psychology and statistics can be defined as a research in which the variable that is changed or manipulated in an experiment, is not under INFLUENCE/CONTROL of the researcher.
This is usually done due to logistical restrictions and or due to ethical reasons.
Some types of Observational study are;
Case Control study
Cross sectional study
Longitudinal study.
An example of Observational study will be observers stationed at a supermarket to see how much processed food versus fresh food was purchased.