A survey is planned to determine the mean annual family medical expenses of employees of a large company. The management of the company 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$.
A) How large a sample size is necessary?
B) If management wants to be correct to within +25$ and-25$, What sample size is necessary?

Question

A survey is planned to determine the mean annual family medical expenses of employees of a large company. The management of the company 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$.
A)	How large a sample size is necessary?
B)	If management wants to be correct to within +25$ and-25$, What sample size is necessary?