General factor of intelligence: sex differences and relationship to school achievement in secondary school pupils

The objective of this research was to examine whether there is a sex difference in general cognitive ability (g) and also investigate mutual relationships between the school achievement and general intelligence. The research was conducted on the Slovak sample of 567 secondary school pupils, 279 of them were male and 288 female. The average age of the sample was 17.1 years (SD = 1.21) and their age ranged from 15 to 21 years. To measure general cognitive ability, The Vienna Matrices Test (Vonkomer, 1992), which is similar to Raven's Standard Progressive Matrices, was used. School achievement criteria were grades in Slovak language, math and foreign language (English, German). The data was analyzed using the non-parametric Mann-Whitney U-test and correlation analysis. It can be concluded that an emerging trend in the literature of negligible sex differences on mean scores of general cognitive ability was replicated (U = 35525.5, p < 0.017, r = -0.10). The results also showed moderately strong relation between general cognitive ability and school achievement - higher general cognitive ability relate to better school achievement in Slovak language (r = -0.38**), math (r = -0.45**), and foreign language (r = -0.35**).