Thanks Michael. I am actually working out of a book and following directions
written by a Microsoft author and am still having some difficulty. It is
becoming a little clearer, but I must be doing something wrong, because I can
not get my answer to replicate the book and I believe the books calculation
is correct.
Thanks again.

"Michael R Middleton" wrote:

David -

Difficult to find detailed help on above function. I get this function not
valid, even if entered as an array formula. I have done this once before
and I know I need to select a region, but it still remains confusing. <

It's usually entered using the Data | Table command.

There's considerable Help on the "data table" topic.

- Mike

www.mikemiddleton.com