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According to a website

"Research, using the Wechsler Adult Intelligence Scale (WAIS III and WAIS-R), that finds general intelligence in favor of males indicates a very small difference.[3] This is consistent across countries.[3] In the United States and Canada, the IQ points range from two to three points in favor of males, while the points rise to four points in favor of males in China and Japan.[3]" What does this mean? Why the difference between America and Asia?