> Obvious conclusion: Gray rats have higher IQ than white rats on average.

Well, they did, didn't they?

The wrong conclusion would be "This is the limit of what white rats can do", which is not how I interpreted GP's comment.

TBH, this is not an easily solved problem: some cultures are better at producing superior students and productive people than other cultures. Those superior individuals are not superior due to inherent traits, but due to environment (culture).

How on earth do you change those under-performing cultures? Any attempt to do so will be met with cries of racism or similar.

[As an aside, my general observation with the the GP's list of IQ is that those cultures who prioritize sport less do better. While GP showed a correlation between race-groups and IQ, I observe the same correlation, but inverse, between sports-focused-cultures and IQ. Removing pro-sports-tracks programs from schools is probably going to do wonders for the bottom 10% of performers in a school]