Discusses a study which compared differences in ratio construction made by high school freshman and junior students. Reports that more freshmen than juniors selected solutions involving one variable, whereas juniors chose solutions that coordinated two variables in a mathematical or verbal rule. Reviews implications in problem solving and concept…

Explains the convergent and discriminant validity of two tests of science process skills with two tests of formal reasoning ability. Reports test results from elementary education majors and discusses the tests' intercorrelations. Implications related to instruction are analyzed. (ML)