On a tree, ripe apples will have an average size.
In a given society, we have a notion of the average person.
These two concepts are not as closely related as one might think, because humans have rather profound volition about the kind of person they want to be, whether or not they think about it in those terms(or at all).
Given the consequences of nonconformity, I suspect there’s an artificially steep bell-curve in the middle; people on the fringes of various attributes, who can, will generally pull themselves towards the center to better match those around them.
And of course, the notion of normal varies tremendously over time and place, so the kind of person who fits effortlessly into the local cultural norm is not necessarily very “normal” at all, compared to whatever genotypical norm humans in an area express.
So if we’re in the business of thinking about people and society, we should not get too wrapped up in the notion that the average person is, in any way, the sort of pure average you think of in non-sentient entities.
If, further, we actually want civilization to succeed, and we believe that division of labor is an important part of that, we should really, really try not to interpret and execute on data in such a way that we build a society expressly for only one kind of person: the kind of person who happens to be, or who can accurately mimic, the local norm.