RBBmba@2014 wrote:Marty,
I hear you here...however, my first reasoning in my last post above seems to be correct,I guess (because the INCONSISTENCY in the sample is explained in the OA -- some Zoo employees having such allergy are MOST LIKELY to be outside the Zoo currently as they've switched jobs with the result that they're NOW part of the GENERAL POPULATION.)

Quick thoughts ?

I find your reasoning hilarious and cool. So, if many zoo employees who experience allergic reactions quit and join the general population, in doing so the former zoo employees drive up the percentage of the general population who experience such reactions, making that percentage likely higher than the percentage of zoo employees who experience such reactions.

At the same time, would it be significantly higher, "substantially more"?

I think that the answer to that question would be "No," as the percentage of of general population represented by former zoo employees is likely relatively low.

So I think the real reason that the percentage in the general population who experience the reactions is substantially higher is that while zoo employees who experience serious allergic reactions can switch occupations, bringing down the percentage of zoo employees who experience the reactions, members of the general population cannot exactly switch to a different population. So the percentage of members of the general population who experience the reactions is as high as the percentage of zoo employees would be were none of those who experience the reactions to switch occupations.