Answer:
A sample of 595 should be obtained.
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:
Estimate of 0.55
This means that
95% confidence level
So , z is the value of Z that has a pvalue of , so .
What sample size should be obtained if she wishes the estimate to be within a margin of error of 0.04?
This is n for which M = 0.04. So
Rounding up,
A sample of 595 should be obtained.