The current study expands on previous research on gender differences and similarities in science test scores. Using three different approaches -- differential item functioning, differential distractor functioning, and decision tree analysis -- we examine a high school science assessment administered to 3,849 10th-12th graders, of whom 2,021 are…

Researchers often compare the relationship between an outcome and covariate for two or more groups by evaluating whether the fitted regression curves differ significantly. When they do, researchers need to determine the "significance region," or the values of the covariate where the curves significantly differ. In analysis of covariance (ANCOVA),…