According to an estimate, the average price of homes in Martha's Vineyard, Massachusetts, was $650,000 in 2011 (USA TODAY, August 11, 2011). A recent random sample of 71 homes from Martha's Vineyard shows an average price of $670,000 with a standard deviation of $25,000. What is the z-score for this sample mean?
a) 0.8
b) 0.4
c) 0.2
d) 1.6
