A survey is planned to determine the mean
annual family medical expenses of employees of a
large company. The management of the company wishes to
be 95% confident that the sample mean is correct to within $50
of the population mean annual family medical expenses.
A previous study indicates that the standard deviation
is approximately $400.
a. How large a sample is necessary?
b. If management wants to be correct to within $25 how
many employees need to be selected?
1 answer