Need psychology help with Psychology Questions about how children interact with each other during the school day

1. A psychologist is interested
in learning more about how children interact with each other during the school
day. The psychologist is particularly interested in discovering the ways in
which children behave when they donot think they are being watched. What research method would be best used to
conduct this type of research, and why? What ethical concerns might be an issue
in this type of research? 

2. 
As a researcher, I am
interested in learning whether or not there is a connection between sleep and
test scores. I want to know if an increase in sleep improves test scores, for
example. What type of research method would I use, and why? What ethical
concerns might present an issue when conducting this type of research? 

3.  If I want to research whether
or not a new medication has an effect
on depression, and I want to compare the medication against a
placebo, what research method might I use, and why? What ethical concerns might
be an issue in this type of research?