My Excel 2000 workbook has two sheets, the first (Evaluation Detail) contains
details about course evalutions per instructor. Column A is Course Name, B
and C are Course Numbers, D is Course Date, E is Training Provider, F is
Instuctor Name, G thru P are evaluation scores and Q is Evaluation Average.

On the second sheet (Evaluation Summary) I want to calculate the overall
course average per instructor, per month. I have written an AVERAGE
statement which calls an IF/AND statement (see below). It works but returns
the same results for each instructor. When I manually calculate the averages
per instructor per date,they are not the same. Can anyone advise as to why
my function is not working. I tried making it an array function
(CTRL+SHIFT+ENTER) but it caused the results to return "0" (and I don't
really understand array functions - :( )!

=AVERAGE(IF(AND('Evaluation Detail'!$D$7:$D$499=DATE(2008,9,1),'Evaluation
Detail'!$D$7:$D$499<=DATE(2008,9,30)),IF('Evaluati on
Detail'!$F$7:$F$499="Thaddeus Thomas",IF('Evaluation
Detail'!$Q$7:$Q$499<0,'Evaluation Detail'!$Q$7:$Q$499,0))))

I greatly appreciate any and all help.
--
LPS