Answer:
We need a sample size of 1068.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of , we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
The margin of error is:
95% confidence level
So , z is the value of Z that has a pvalue of , so .
In this problem:
We need a sample size of n.
n is found when
We do not know the exact proportion, so we use , which is when we are are going to need the largest sample size. So
Rounding up
We need a sample size of 1068.