We don't really know the answer to your question because PMI only says that exams are scored based on "sound psychometric analysis".
But... what we do know is that students have had "Needs Improvement" or "Below Target" on their exam report and they still passed. So if you are doing badly in one domain but you are doing really well in another, that will offset things and you can still pass.
Until Next Time,
Cornelius Fichtner, PMP, CSM
President, OSP International LLC