I tried that but for some reason it didn't work. It seems like it
would, but the totals do not add up correctly. This is the exact
formula I typed into my Analysis page:

=AVERAGE(INDEX('RawData'!$B$2:$IV$65000,,MATCH(B$1 ,'RawData'!
$1:$1,0)))

B1 (on the Analysis page) contains the account number I want.