We collected data on first-year rural middle school (seventh-grade) students in two prefectures in two provinces in Northwest China.
We created our sampling frame in three steps. First, we included all 19 counties within the two prefectures in the study. Second, we obtained a list of all 343 junior high schools in the 19 sample counties that had at least one seventh-grade class. We excluded junior high schools with 20 or fewer students in the seventh grade as well as schools typically not counted as rural schools, such as those located in the county seat.
并且文章中還有很清楚的原始數據表格，這些都是公開的。既然我們產生了對於數據的分歧，那就説明維基百科已經不足以支撐本場討論，因此你需要拿出原始的研究論文和數據來進行進一步討論。你所説的“查德·林恩/塔圖·萬哈寧《IQ and Global Inequality》”，我相信這2位是正經的學者，那麽有關這方面的論文也應該可以被找到。
剛好Richard Lynn有個research gate 賬號，在這個頁面，他本人回應了有關IQ and Global Inequality的批評。其中:
We would like to reply to the criticisms of our book IQ and the Wealth of Nations (Lynn and Vanhanen, 2002) made by Ervik (2003). Our book presents mean IQs for 81 nations obtained from the administration of intelligence tests to samples of the population, and shows that these are substantially associated with per capita income and economic growth from 1820. We argue that there is a causal relationship from IQ to these economic indices.