=SUM(SUMIF(A1:A10,{1,3,7},B1:B10))/SUMPRODUCT((A1:A10={1,3,7})*(B1:B10<""))

would give the average for group numbers 1, 3, 7 in column A.

--
Regards,
Tom Ogilvy

"dkingston" wrote:

i have a simple table where column A contains group #s and column B contains
values.
i need to find the average of multiple groups within the table and ignore
rows where the value column is blank. the # of members within each group may
change and i would prefer not to have to sort by group # if that's possible.
thanks in advance for your time.