Final answer:
A comparison of lifestyles between people with and without lung cancer is a case-control study, which is a form of observational study that helps identify correlations between past behaviors and present conditions.
Step-by-step explanation:
An experiment comparing the lifestyles of people with lung cancer and those without is an example of a case-control study. A case-control study is a type of observational study that compares a group of subjects having a specific trait (cases) with a group of similar subjects without the trait (controls). This research is often retrospective, asking participants about past behaviors to find correlations with current statuses, like the association between smoking and lung cancer found in Doll and Hill's landmark study. While these studies can provide useful data, it is important to note that they show correlations, not causation, due to their non-experimental nature.