WageWeb (http://www.wageweb.com/health1

.htm) is a service of HRPDI and provides compensation information on more than 170 benchmark positions in human resources. The October 2003 posting indicated that labor relation managers earn a mean annual salary of $86,700. Assume that annual salaries are normally distributed and have a standard deviation of $8850.

a. What is the probability that a randomly selected labor relation manager earned more than $100,000 in 2003?

b. A sample of 20 labor relation managers is taken, and annual salaries are reported. What is the probability that the sample mean annual salary falls between $80,000 and $90,000?