It varies among races, knowledge of this is scientifically sound, it is the consensus of everyone who studies it seriously.
The modern tendency is to feverishly avert one's eyes from this fact, but it must be reckoned with eventually.
I believe we'll all be better off when we can stop the hand wringing of why isn't group X doing activity Y.
The sooner we can get on with building a society that is better for everyone while taking everyone's capabilities into account the better.
Not to say there are strict limits on capabilities, but groups with higher average intelligence are obviously going to win more Physics Nobels.