Answer:
The minimum number of cities we need to contact is 96.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence interval
, 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 interval
So , z is the value of Z that has a pvalue of
, so
.
In this problem, we have that:
The minimum number of cities we need to contact is 96.