Hi Rob,

There may be an easier way, but here's an array formula that should work for
you:

=SUM(((B1:B13)0)*((C1:C13)0)*((B1:B13)-(C1:C13)))/SUM(((B1:B13)0)*((C1:C13)0))

Since it's an array formula, you must enter it with Ctrl+Shift+Enter.

--
Regards,

Jake Marx
MS MVP - Excel
www.longhead.com

[please keep replies in the newsgroup - email address unmonitored]


RobPaolillo wrote:
I am trying to write a VBA code that will average the difference of
of 2 arrays ignoring the rows where one array is missing data. In the
example below Jul 4 Jul 9th and July 12 and July 14, need to be
ignored. If this can be done in VBA or within a XL formula, any
solution is welcome.

Thanks in advanced.


A B
2-Jul-04 3 4
3-Jul-04 4 5
4-Jul-04 _ 3
5-Jul-04 6 4
6-Jul-04 7 1
7-Jul-04 77 23
8-Jul-04 3 2
9-Jul-04 5 _
10-Jul-04 5 4
11-Jul-04 45 35
12-Jul-04 _ 5
13-Jul-04 1 2
14-Jul-04 1 _

incorrect differece avg -- 5.307692308
correct difference avg -- 7.888888889