Average Top15 minus the Top2

Hi,

I want to have an average from the values of the lowest Top15 minus the Top2 (so Nr3, 4, 5, etc till 15) of a column.

I’ve already got:

Output_ranking =
RANKX (    ALLEXCEPT ( RAW, raw[AVG_VSIBASE] ),    CALCULATE ( SUM ( RAW[Output] ) ),    ,    ASC
)

To rank the values

and

Output_IF = IF (
and (
raw[Output_ranking] <15,
raw[Output_ranking]>2),
"Y","N")

To determine Top3 until Top15

When I want to this:

Measure = CALCULATE (              SUM(raw[Output]),              raw[Output_IF]="Y"              )

 I get some errors (see printscreen)

What's wrong? 

Thnx, Manfred