Discussion:
Q: Families USA, a monthly magazine that discusses issues related to health and health costs, surveyed 18 of its subscribers. It found that the annual health insurance premiums for a family with coverage through an employer averaged $10,450. The standard deviation of the sample was $985.
(a) Based on this sample information, develop a 90 percent confidence interval for the population mean yearly premium. (Round up your answer to the next whole number. Omit the "tiny_mce_markerquot; sign in your response.)
(b) How large a sample is needed to find the population mean within $264 at 90 percent confidence? (Round up your answer to the next whole number.)