A random sample of 400 town voters were asked if they plan to vote for Candidate A or Candidate B for mayor. The results were sorted by gender and are shown in the table below.
| Plan to vote for Candidate A | Plan to vote for Candidate B | |
|---|---|---|
| Female | 202 | 20 |
| Male | 34 | 144 |
The town has a total of 6,000 voters. Based on the table, an estimate is made of the number of voters who plan to vote for Candidate A. Which of the following is the most important assumption for this estimate to be reliable?
The sample size of 400 is exactly 1/15th of the total voter population.
The town's total voter population is exactly 6,000.
The sample is representative of the entire voter population.
The voters were asked about their preference in person.
