Racially/regionally skewed tests

It’s said that IQ and other tests are skewed towards Western/white bias. And I’m not inclined to disagree. But I’m at a loss when it comes to quantifying the bias. How would we do so?

  1. I’m sure there’s statistics proving the case. But that doesn’t lead to understanding. Has anyone put forward some kind of explanation for why this happens, and how?

  2. Assuming we can make some kind of region/ethnicity/cultural background neutral test, what form would it take or how would the questions differ? Has such a test been invented?

  3. Not that the racists would take the bait, but it would still give me some small comfort if we could devise an IQ test which non whites (other than Asians wink wink) excelled at compared to whites. In what manner could we bias such tests against “whites/Westeners” and towards “non whites/non Westerners”?