Bea asks Brian the sample size and the timeframe.
Brian responds, 140,000
Suppose the bank has one million customers in the USA (where the survey is conducted)
With a 95% confidence level and a margin of error of 3%, what would you recommend the minimum sample size to be?
This is the minimum sample size. In practice, there would be some adjusted increase for an estimated response rate.
n = p(1-p)(Z/E)^2 =
This solution shows details of how to calculate the appropriate sample size from the information provided.