Final answer:
The data set of the political party of every U.S. President is a population, not a sample, because it includes all members of the specified group with no exceptions, and each president's political affiliation is a distinct element in the presidential history.
Step-by-step explanation:
When considering whether the data set of the political party of every U.S. President constitutes a population or a sample, the correct option is 1) Population. The distinction between a population and a sample lies in the comprehensiveness of the data collected. A population includes all members within a specified group, whereas a sample represents only a subset of that group. In the context of U.S. Presidents, the data set including the political party of every individual who has ever held the presidency is a complete set, therefore representing the population. There are no more members to include, and each president has an equal and fixed presence in this data set.
If a researcher were to look only at the political parties of presidents within a certain time frame or under specific conditions, that would constitute a sample, as it would not include all past U.S. Presidents. However, since the question pertains to the set of political parties of all presidents, it is the entirety of the group of interest, making it a population. Political analysts collect data about the entire group without needing to generalize findings beyond that group, hence eliminating the need for sampling.
Another key point to consider is that each U.S. President serves a unique role, and therefore their political affiliation is an entire data point within the population of presidents. Unlike polling where a sample is representative of a larger group's opinions, the political party of each president is a distinct element in the political history and cannot be considered a subset intended to represent a larger set.