Which example best illustrates research with human subjects according to federal definitions?

The example of conducting an online focus group with cancer survivors and their significant others best illustrates research with human subjects according to federal definitions. This is because it involves direct interaction and engagement with individuals who have specific characteristics (cancer survivors and their significant others) and seeks to gather qualitative data through discussion, opinions, experiences, or personal insights.

Research with human subjects, as defined by federal regulations, typically involves collecting data about individuals through intervention or interaction or obtaining identifiable private information. In this case, the focus group setting ensures that detailed personal experiences and potentially sensitive information are shared, making it a clear example of research involving human subjects.

The other examples, while they involve data collection, do not meet the same criteria. For instance, collecting data from anonymized web forms does not engage with identifiable individuals directly, and therefore does not constitute research with human subjects. Similarly, while administering a quiz about health knowledge gathers information, it does so in a less interactive, less personalized manner compared to the focus group. Surveying visitors on a health website could involve data collection without directly interacting with identifiable individuals, thus falling short of the federal definition focused on human subjects.