Families USA, a monthly magazine which discusses issues related to health as well as health costs, surveyed 21 of its subscribers. It found that annual health insurance premiums for the family with the coverage through employer averaged $10,895. The standard deviation of the sample was $1,145.
(a) Based upon this sample information, construct a 98 percent confidence interval for population mean yearly premium. (Round up your answers to the next whole number. Omit the "tiny_mce_markerquot; sign in your response.)
Confidence interval for the population mean yearly premium is between $ ? and $ ? .
(b) How large a sample is needed to find the population mean within $232 at 99 percent confidence? (Round up your answer to the next whole number.)
Sample size ?