Question

Option 1: The volunteers are split into 2 groups by a random process. One

group will read the article and the other will not. Everyone will then look at
the city pictures and the diameter of their pupil will be measured while
they look at the pictures. *
Option
Survey
Observational study
Experimental study

Answer 1

Experimental study

Explanation:

experimental studies are controlled by the researcher and often the participants are grouped randomly. An difference in the data observed of both groups would be due to intervention of the experimenter.