Look, Jack - I'm fairly sure that there's no malicious intent in your OP, but that exact moment that a society accepts that one race is less intelligent than another race, in that moment, the so-called 'less intelligent' race officially becomes an underclass, to be shunned in society and in business by those not of that race...and the young people of that race would become all the more rebellious and would take their frustration out on those not of their race.
Now I figure that you never had any intention for such to happen...but that's what WOULD happen, as anyone who grew up in the MS Delta can tell you from first-hand experience - for nowhere else in America is there such an entrenchment of social classes based on race.
I mean, really, Jack - what's going to happen on a college campus when it says there in the textbook that due to biology, Hispanics and/or blacks are more likely to have lower IQ's? While a merely objective discussion by real scientists of differences in intelligence between the races might sound reasonable, in the modern day that such discussions are almost impossible to keep secret, the moment such discussions become public would greatly - and irrevocably - damage the fabric of society. One (or more) race becomes an underclass - permanently, mind you - and the friction between that race and the favored race (especially among young men with Constitutionally-guaranteed access to firearms) will often turn deadly. You REALLY don't want to go there.
So...yes, there ARE subjects that are never, ever wise to broach. This is one of them.