averaging rows based on a cell = "value"???

[deras]

i have 7000 rows of numberical data, the first column of each row i
composed of 16 category identifiers. how do i compose a formula t
just get the average row scores for individual category identifiers

 

[Frank Kabel]

i have 7000 rows of numberical data, the first column of each row is

composed of 16 category identifiers. how do i compose a formula to
just get the average row scores for individual category identifiers?

Hi
try something liek
=SUMIF(A1:A7000,category_id,B1:B7000)/COUNTIF(A1:A7000,category_id)

Frank