| A | B |
|---|
| Individuals | objects desc. by data set |
| Variable | can take diff. values for diff. individuals |
| observational study | observes individuals and measures variables of interest |
| sample surveys | kind of observational study |
| population | entire group of individuals |
| sample | part of pop. from which we acutally collect info. |
| censu | sample survey that includes entire population |
| experiment | imposes treatment to observe response |
