Hello everyone,
really sorry for my poor english.I'm trying to normalizie a price series,starting a certain price(i.e 40 bars price ago).This will be my base((ref(C,-40)/ref(C,-40))*100.Then,the following price will be (Ref(C,-39)/Ref(C,-40))*100 and so on.
How can i write it in Metastock language?
Thank you

 You can do something like below if you are trying to nail down a price at a specific time:

a1:=If((Year()=2009) AND (Month()=5) AND
  (DayOfMonth()=20),C,PREV);
a1

I am guessing that is what you are looking for.

Thank you,johnl, for your reply.