Answer:
A margin of error of +/- 3%
Explanation:
Strenght of surveys:
The lesser the margin of error, the more precise, stronger, the confidence interval is.
The margin of error depends of the number of people surveyed. The more people are surveyed, lower the margin of error is, giving a stronger interval.
In this question:
We want the smaller margin of error, which is given by:
A margin of error of +/- 3%