In a book called The Wild Woods Guide, the authors present a table of cloud types with some characteristic features. Stratus clouds are listed as having an average cloud height of "0 -- 450 meters." Well, first off, how can a cloud be zero meters in height (not zero meters from the ground -- its own height is the average here)? Wouldn't that be no cloud? Or when it looks perfectly clear, is the sky actually filled with zero height stratus clouds?
What's more, what kind of "averages" are they giving in the table? (They are ranges for all cloud types.) The mean, median, and mode all give you a single number, not a range. And this is not an isolated instance, I see these "averages" all the time, e.g.: "Joe Smith averaged between 15 and 30 home runs a year during his career."