1) Test Methodology is nothing but implementation of test
strategy i.e description of test levels in which several
test activities are performed. As from testing perspective
integration testing, system testing uses black box testing
methodology. Unit testing uses white box testing methodology.

2) Test data is a real time data prepared with the help of
use cases or sent by the client side. It is used to test the
condition using real time data. 

3) Test scenario is nothing but a sequential steps followed
to design test cases. EXAMPLE: to test ATM withdrawal
process we create scenarios. 

4) Test environment controlled environment replica of real
time environment where where would be executing our test cases.

I tried my best to answer above questions now lets hear what
other members have to say on the above
Thanks