I have a set of a measure for which the average is -.074. The range of the individual row values is between .060 to -.176. Is there away to create a column that will display the difference between a given row value and that average?

Basically, I'm trying to dynamically create a calculated field that displays the equivalent of:  [MyData] - AVG([MyData]). When I try that I get an error about mixing aggregate and non-aggregate arguments.

Thanks,

Tony