Your formula:
=STDEV(IF((C2:C204)*(P2:P2040),P2:P204))
should work...are you confirming it as an array formula (Ctrl+Shift+Enter)?

This should be taking any number in P2:P204 that is greater than 0 and has a
value other than 0 in the C column.

--
Best Regards,

Luke M
"Researcher" wrote in message
...
I would like to use the STDEV function on a set of cells that have been
indicated by a conditional statement. I have tried a variety of ways and
have
not been able to get it to work using others suggestions. I am wondering
if
anyone knows. I have Excel 2007, I am not sure if this has affected my
results. Below is one thing that I tried, that seemed to have worked for
others.

=STDEV(IF((C2:C204)*(P2:P2040),P2:P204,""))

When looking at the array it returns the value of 15 for every cell that
is
in the specified range.
Thanks.
Researcher