Question

The National Coalition on Healthcare suggests that the mean annual premium that a health insurer charges an employer for a health plan covering a family of four averaged $12700 in 2008. A sample of 30 families of four yield a mean annual premium paid by their employer to be $13200 with a sample standard deviation of $300. We are interested in whether the mean annual premium that a health insurer charges an employer for a health plan covering a family of four is different from $12700 using a significance level of 0.10.