Two studies of Atheism and Theism.

[Mister Agenda]

I can't be arsed to cite it, but I recall reading that the difference in IQs between theists and atheists turns out to be very specific if it you break it down: atheists tend to be better at estimating.

Estimating in what sense? I'm a little confused. Like numbers only? Or estimating correct things vs incorrect things?

Numbers, probabilities, and visual comparisons, like whether two lines are the same length or different.