Larissa and Marta are both interested in researching cell phone use among elderly individuals. Larissa attends events that are marketed at seniors (e.g., Bingo night) and counts how many of the participants use their cell phones during the event. Meanwhile, Marta goes to the mall and hands out surveys on cell phone use to people who appear to be over age 70.
In this example, Larissa's research is observational; self-report, while Marta's research is a case study; experiment.
