mdx query

I want to display headcount which is more than (>5) . this is the query

SELECT
Non empty{[Time].[School Year].[School Year]*{[Measures].[Headcount]>5}} ON COLUMNS
, HEAD(NonEmpty([Schools].[School Name].[School Name],Axis(0)),25) ON ROWS
from
[Enrollment] CELL PROPERTIES VALUE, FORMATTED_VALUE, FORE_COLOR, BACK_COLOR
please help me, if i will remove (>5) it is displaying report .
I am getting error.

Executing the query ...
Query (2, 46) The function expects a tuple set expression for the 1 argument. A string or numeric expression was used.
Execution complete