Question

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?
A. Not enough information given.
B. survey
C. observational study
D. controlled experiment

Answer 1

Observational study

Answer 2

ok:)

Answer 3

Not right I just took the test and used observational Study--got it wrong!

Answer 4

controlled experiment