Not at all, I trust statistics a great deal. I don't have statistics on the reliability of the SAT nor how reproducible it is, so I have no way to know based on

Not at all, I trust statistics a great deal. I don't have statistics on the reliability of the SAT nor how reproducible it is, so I have no way to know based on the numbers presented how noisy the distributions ought to be. You can imagine that some band of test-takers is on the bubble and can fall above or below the "top-tier" line on any given day. You are asserting that this is less than 1% of the population, I'd argue it's likely higher than that. But I don't believe I have the data to present either way. To address the population; if the "population" you are referring to is only the seniors in Michigan on _that_ day then it's might be pretty accurate. Looks like the population of Michigan is around 10 million (20% of that is under 18), meaning that this would be extrapolated much more to address just the population of Michigan, not to mention what it means if we apply it to the entirety of the united states. Any population that we apply this to that isn't the sample audience at that specific time will incur some error. At each of these higher levels of population abstractions we have orders of magnitude higher error margins, which would quickly dwarf the ppt difference between males and females in a single test.