Trio an Iteractive Graphic System for Demand Model Estimation.

This Article Gives a Summary Description of Trio, an Interactive Graphic Program Developed for the Formulation and Simulation of Regression Models Belonging to Three Broad Classes and the Analysis of and Reporting on Data and Model Results. the General Design of the Data Bank and the Structure of the Program Are Discribed. Twelve Model Types Belonging to the Three Classes of Level, Share and Probability Are Surveyed and Examples of Graphic Output Are Shown.