Final answer:
A researcher observing how many people are using a local park is an example of naturalistic observation.
Step-by-step explanation:
A researcher observing how many people are using a local park is an example of naturalistic observation. Naturalistic observation is a research method where the researcher observes and records behavior in its natural setting without intervening or manipulating variables. It is commonly used in the field of social studies to gather data about human behavior and social interactions.