of analysis is a population, not an individual.
What have you learned from this lecture? Well
you now know the definition of an experiment,
if you recall, an experiment is when you,
the investigator manipulates a variable in
the study. You now know the purpose of blinding
and randomization. Randomization is about
controlling for extraneous variables that,
as a result, improve our internal validity.
You now know the characteristics of the different
kinds of experiments, the RCT, randomized
controlled trial, the quasi-experimental design
and the natural experiment, as well as this
thing that I've called the ecological study,
which isn't strictly an experiment, but we
tend to talk about it with experiments. And
you also understand the nature of Hawthorne
and Rosenthal effects, which are kinds of
biases we encounter a lot in RCTs and which
are the reason that we prefer blinded studies.