William Saletan in Slate:
Among white Americans, the average IQ, as of a decade or so ago, was 103. Among Asian-Americans, it was 106. Among Jewish Americans, it was 113. Among Latino Americans, it was
89. Among African-Americans, it was 85. Around the world, studies find the same general pattern: whites 100, East Asians 106, sub-Sarahan Africans 70. One IQ table shows 113 in Hong Kong, 110 in Japan, and 100 in Britain. White populations in Australia, Canada, Europe, New Zealand, South Africa, and the United States score closer to one another than to the worldwide black average. It’s been that way for at least a century. Remember, these are averages, and all groups overlap. You can’t deduce an individual’s intelligence from her ethnicity. The only thing you can reasonably infer is that anyone who presumes to rate your IQ based on the color of your skin is probably dumber than you are.
So, what should we make of the difference in averages?
More here.