IQ bell curve
If the group in question has a mean IQ of 85 — the probability you produce people who are scientist caliber (130 IQ+) is a mere 0.0013. If your group has a mean IQ of 110 — the probability skyrockets to 0.0912. If we take 2 such hypothetical groups with N=100,000 then the 85 IQ group would be capable of producing only ~130 scientists. The 110 IQ group would be capable of producing a whooping ~9120 scientists. - AryAMsha
Tests
If one is sufficiently self-aware, intellectual deficits can be compensated for by giving the brain more focus, time and training. More often than not, the clock is the killer in these tests.