# SUMIF look to previous row

I want to make SUMIF in Google Spreadsheets to look at the previous row for its evaluation. So if my sheet looks like this:

trigger     value1

something   value2


I want it to add value2, because the trigger is in the previous row. Can this be done with SUMIF and if not, is there another way?

=sumif(A2:A15, "<6", B3:B16)