To estimate the excitement level of a new car, a researcher assigns a number to every address within a certain zip code, then uses a random number generator to select households to survey. What is the purpose of assigning a number to every address within a certain zip code?
1) To determine the popularity of the new car model
2) To identify potential customers for the new car
3) To ensure a fair and representative sample for the survey
4) To track the geographical distribution of excitement levels