rural chinese iq

Would it be too hypothetical to argue that the inability to do no better than seventh-grade math at age seventeen argues for an individual IQ somewhat below 100? On the recent international test of thirteen-year-olds noted in Chapter 5, in which mainland Chinese students were scoring 80 on seventh-grade math tests compared to the U.S. 55, and given these often rural Chinese were scoring at about 101 IQ even with an as yet undeveloped educational system, the above estimate for an average U.S. intelligence may not be far off the mark.