How do i perform calculations on filtered data
 

I have a long, two column list. I can sort the data easily with a pivot
table, but I want to summarize the data with a TRIMMEAN function. How do I
reference the table's source data easily? Previously I have manually defined
names for cell ranges and referenced those in my functions. but this is too
laborious for the amount of data I now have.

-Thanks for any help.