The mean and the average are the same thing. The mean of a list of numbers is the sum of the numbers divided by the number of items in the list.That's why "average" in many cases is useless - you need to look at the mean
Case and point - the highest *average* salary for a grad (bachelors degree) from UNC for a long time was History. Why? Michael Jordan - obviously the mean was much lower but his exorbitant success made the average for History majors balloon through the roof.