Answer:
A sample size of 345 is needed so that the confidence interval will have a margin of error of 0.07
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 of the interval is given by:

In this problem, we have that:

99.5% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
Using this estimate, what sample size is needed so that the confidence interval will have a margin of error of 0.07?
This is n when M = 0.07. So







A sample size of 345 is needed so that the confidence interval will have a margin of error of 0.07