Question

Please double check for me...
Researchers randomly choose two groups from 15 volunteers. Over a period of 9 weeks, one group watches television before going to sleep, and the other does not. Volunteers wear monitoring devices while sleeping, and researchers record dream activity. Which type of study method is described in each situation?
I think it's either going to a A or D
A. Not enough information given.
B. survey
C. observational study
D. controlled experiment

Answer 1

they have control over the experiment. enough info is given, therefore it is D

Answer 2

Its probably D.