One way....
(assuming your data is in columns A and B and in rows 1 to 10 - adjust to
suit, but you must maintain an equal number of rows in the formula!)
=SUMPRODUCT(--(A1:A10=""),--(B1:B10="yes"))

Or......
=COUNTIFS(A1:A10,"",B1:B10,"Yes")

Rob


"CraigMacE" wrote in message
...
I have two columns, the first has a list of numerical values and the second
has yes or no values. I want a formula to count the number of times a
"yes"
appears without a number in the other column.