UNIVERSITY STUDENTS ’ EXTENSION OF LINEAR MODELS TO NON-LINEAR SITUATIONS

This communication presents a study of university students ' extension of linear models to non-linear situations. By linear models we mean the model y�a.x+b, particular representations of direct proportionality and the diagram for the rule of three. This phenomenon has been studied at the primary and secondary levels, and has been called “illusion of linearity ” or “linear misconception ” (Behr, Hare, Post, &amp