Answer:
The population of interest to the agent is the fifty randomly selected houses sold in that period.
Step-by-step explanation:
The population of interest is the target population the researcher is trying to draw an inference about from the collected data sets.
In this case, the agent is trying to draw inference from the fifty randomly selected houses sold in a particular period in order to estimate the mean number of days on the market of all houses sold in the last two years in Union County. He does this by examining the sales data of these selected houses.