Send back a statistical form (6)
I believe the answer is:
return
'send back' is the definition.
(thesaurus)
'a statistical form' is the wordplay.
'a statistical' becomes 're' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'form' becomes 'turn' (turning is a kind of forming).
're'+'turn'='RETURN'
Can you help me to learn more?
(Other definitions for return that I've seen before include "answer" , "reply" , "second half of journey" , "Send/come back" , "Retort" .)