Statistical average (4)
I believe the answer is:
mean
'statistical average' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for mean that I've seen before include "Stingy in average way" , "of little value" , "Stingy; five Dn" , "Spiteful -- excellent (slang)" , "Signify; tight" .)