You are correct. I should have thought of that. They are alpha numeric
sometimes with a dash.

"T. Valko" wrote:

Here's a small sample file using your posted data that demonstrates this.

zNadine.xls 14kb

http://cjoint.com/?eCdSeTo64Y

As you'll see the formula (which doesn't have to be array entered) returns
the correct result.

If you're getting an error I suspect that your invoice #s aren't really
numbers like your sample data, or they may look like numbers but they're
really TEXT numbers. TEXT numbers and NUMERIC numbers are not the same.

--
Biff
Microsoft Excel MVP


"Nadine" wrote in message
...
Didn't work. :( Result was #N/A as an array formula. Thanks for trying.

"T. Valko" wrote:

Try this array formula** :

=AVERAGE(IF(FREQUENCY(A2:A9,A2:A9),B2:B9))

** array formulas need to be entered using the key combination of
CTRL,SHIFT,ENTER (not just ENTER). Hold down both the CTRL key and the
SHIFT
key then hit ENTER.

--
Biff
Microsoft Excel MVP


"Nadine" wrote in message
...
I have a column of invoice numbers and multiple rows of data pertaining
to
each one. So one invoice number could have 10 rows of data pertaining
to
it
so the invoice number will be repeated 10 times. Then on each line is
the
time it took to receive the data so this number will be the same on all
10
lines. I have hundreds of rows of data but only a handful of invoice
numbers. I need to find the average of the days based on the unique
count
of
the invoice numbers. I already have my formula for the unique count
but
now
need one for the average when the invoice numbers are not in contiguous
cells
down the column.

Example:
Col A Col B
Invoice # # Days
12345 11
12345 11
12345 11
98995 15
66438 37
12345 11
98995 15
12345 11

So there are 3 unique invoice numbers. How do I write the formula to
find
the average number days it took to receive all three? I'm in Excel
2003.


.



.