Researchers randomly assigned adolescents to either a single-grade classroom or a mixed-age classroom. This is an example of a __________.
A. naturalistic observation
B. case study
C. natural experiment
D. field experiment
Answer:D
Researchers randomly assigned adolescents to either a single-grade classroom or a mixed-age classroom. This is an example of a __________.
A. naturalistic observation B. case study C. natural experiment D. field experiment