Final answer:
Sets like family, friends, and coworkers, as in Justin's wedding guest list, are typically well-defined based on clear characteristics or relationships. Even broader sociological concepts, such as family, can have fluid definitions in society but may be rigid for official purposes like census taking.
Step-by-step explanation:
The question asks if each set that Justin created for his wedding guest list is well-defined. A well-defined set is one where it is clear whether an element belongs to the set or not. In Justin's case, the categories of family, friends, and coworkers would likely constitute well-defined sets since each guest can be clearly categorized into one of these groups based on their relation to Justin. The recorded lists of who attended and who did not would also be well-defined, as an individual can only be in one of these two categories, that of having attended the wedding or not.
When considering different groups in society, it is evident that groups like coworkers, family, and friends can be well-defined based on shared characteristics or relationships. Furthermore, a marriage can be seen as a well-defined institution where individuals have met certain criteria to be considered married, often validated by a societal or religious ceremony, as seen in Rebecca and John's church wedding.
In broader sociological terms, the concept of family can be more fluid, reflecting the diversity and less structured nature of family arrangements in modern society. However, for purposes such as census and studies, a more rigid definition may be applied to ensure consistency and allow for tracking over time, such as the U.S. Census Bureau's definition of a family.