try below. and if does not work, please attach sample data as twbx format.
IF LOOKUP(ATTR([Turbulence]), -1) < 0
THEN sum([52 Week Change])
sum can be min. I am not sure
Tableau accepts the calculation, however, the effect I wanted isn't showing on my chart. I've attached the workbook file. I basically want to fill in the grey gaps (grey representing the 52 week range) in Sheet 2 with green if the last Turbulence value is positive or red if negative. It is also adding random spikes where the 52 week range is -1 or 1.
Thanks for your help,
I actually found a workaround that doesn't need to use lookup. My problem is now resolved.