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# What is the confidence interval for the population mean yearly premium for Families USA, a monthly magazine?

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 "\$" 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 \$264 at 90 percent confidence? (Round up your answer to the next whole number.)

#### Solution Summary

This solution shows how to develop a 90 percent confidence interval for the population mean yearly premium, formatted in an attached Word document.

\$2.19