Column A is Date ie. 2-Feb-2007
Column C is # of items
and Column E is Accuracy .ie 97.13%

I need to multiply every item selected by its accuracy then add them and
divided by the sum of items. ie. (c5*e5)+(c6*e6)+(c7*e7)/c5+c6+c7

To make it a little more difficult i have to do this for each month of the
year.
Thanks in Advance for any help