Well, the average is just the sum divided by the count, so I'd use sumif and
countif:
=sumif(a:a,7,b:b) / countif(a:a,7).
If you put the series of numbers 0-19 in d1:d20, then you can use cell
references for the 2nd argument in the sumif and countif functions. In e1:
=sumif(a:a,d1,b:b) / countif(a:a,d1). Then autofill that down through e20.
--Bruce

"Metolius Dad" wrote:

Dear Wizards,

Col A has 200 - 300 entries randomly occuring limited to the integers 0-19.
Col B has numeric values. What formula can I use to figure the average of
all of col B's values that are accross from (associated with) a col A value
of '7' then '8' then '9' etc.

Thanks for being there.
Sam