Answer:
Unrepresentative Sample
Explanation:
A sample that doesn't represent the whole of the population then such a sample is said to be unrepresentative. The research is useless if the the sample choosed is not sufficient to represent the whole of the population. The researcher try to mitigate by using a number of sampling techniques to make sure that the sample is a good representative of the population.
The questions clears that the researcher wants to know about the US population's occupation. But what he did is choosed a town of 100 residents and is forming an opinion on that sample. The opinion formed on such a small and unrepresentative sample would be obviously inappropriate.