Question

state whether the collection is a sample or a population: social security numbers are held by the irs for every american worker (in theory). population sample

Explanation:

A population is the entire group of interest. Since the IRS has Social - Security Numbers for every American worker (the entire group of American workers), it represents the population. A sample is a subset of the population. Here, we have the whole set of American workers' Social - Security Numbers, not a subset.

Answer:

population