The sample mean of the annual salaries of a group of 100 accountants who work at a large accounting firm is $130,000 with a sample standard deviation of $20,000.
If a member of this group is randomly chosen, what can we say about
(a) the probability that his or her salary is between $90,000 and $170,000?
(b) the probability that his or her salary exceeds $150,000?
Hint: Use the Chebyshev inequality.