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Johnson, Wendy; Deary, Ian J.; Bouchard, Thomas J., Jr. – Educational and Psychological Measurement, 2018
Most study samples show less variability in key variables than do their source populations due most often to indirect selection into study participation associated with a wide range of personal and circumstantial characteristics. Formulas exist to correct the distortions of population-level correlations created. Formula accuracy has been tested…
Descriptors: Correlation, Sampling, Statistical Distributions, Accuracy
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Wicherts, Jelte M.; Dolan, Conor V.; Carlson, Jerry S.; van der Maas, Han L. J. – Learning and Individual Differences, 2010
In his comment on our literature review of data on the performance of sub-Saharan Africans on Raven's Progressive Matrices, Lynn (this issue) criticized our selection of samples of primary and secondary school students. On the basis of the samples he deemed representative, Lynn concluded that the average IQ of sub-Saharan Africans stands at 67…
Descriptors: Legislators, Academic Achievement, Intelligence Quotient, Foreign Countries