Comparison of fluid intelligence in female and male high school students based on classic and item-response theories

Sex differences in intelligence is one of the most important topics in contemporary psychology. Some findings indicate that there are sex differences in intelligence and some others believe that there is no sex differences in general intelligence. Some authors believe that this conflict can be resolved by fluid intelligence، which is conceived as the core of intelligent behavior. The aim of this study was to compare fluid intelligence in female and male high school students based on classic and item-response theories. A total of 884 high school students (446 males، 438 females) ranging in age from 15 to 17، were tested by Scale 3 (form A) of Cattell''s Culture Fair Intelligence Test (CFIT). Cronbach’s alpha coefficients for female and male students were 0. 87 and 0. 85 respectively. Statistical testing showed that: 1) the raw mean score of female students on fluid intelligence was significantly higher than that of male students، 2) comparison of the abilities of the two groups based on IRT model showed that the abilities of female students on 25 percentile and below were lower than that of male students، and the abilities of the two groups between the 25 to 55 percentiles were identical، the abilities of female students between the 55 to 85 percentiles were higher than that of male students، and the abilities of male students on 90 percentile and above were higher than that of female students.