Final answer:
Observational data refers to the data collected from observing and examining an experimental intervention in an observational study. This type of study is used when experimental studies are not possible or ethical.
Step-by-step explanation:
The data collected from observing and examining an experimental intervention is called observational data. In an observational study, the researcher records and measures naturally occurring phenomena without directly manipulating the independent variable. This type of study is used when conducting experimental studies is not possible or ethical. For example, if researchers want to investigate the relationship between malnutrition and elementary school performance, it would not be appropriate to assign an experimental group to be malnourished, so an observational study would be conducted instead.