One thing I have wondered about is the generally low levels of education, both high school and college, in Southern states. I also know that many Southern states have high African-American populations, and this is a group that often is (statistically speaking) weak in education.
I bet the reader doesn't have to think very far for the various uncomfortable conclusions that could possibly be derived from looking at this.
But actually, when you look at things closely, it is better. Especially in this case:
Alabama is a good test bed for this, because it has a large number of counties, and they vary from 1 to 70% African-American. And across these counties, as you can see, the education tends to be fairly uniform: and for that matter, uniformly bad. Jus' sayin'. There are counties in Alabama between 60 and 65% high school graduation rate that are almost totally white, as well as counties with those numbers that are majority black. The one thing that is absent is any counties in the upper right: there are no majority African American counties with high high school graduation rates. Although Montgomery and Jefferson do come close.
What is interesting about this is there could be an assumption that is actually backwards. The reason why African-Americans, in the US, have lower education rates might actually be an artifact of the fact that many of them live in the rural south, where EVERYONE has low education rates. At least in part.