A random sample of 15 hourly wages for restaurant servers in Liverpool (including tips) was drawn from a normal population. The sample mean and sample standard deviation were = 14.9 and s = 6.75.

(a) Can we infer at the 5% significance level that the mean wage for restaurant servers (including tips) is greater than 12?

(b) Can we infer at the 5% significance level that the population mean is greater than 12, assuming that you know the population standard deviation is equal to 6.75?