On Mon, 28 Sep 2015, lorenzosmeraldi(a)libero.it wrote: Short answer: yes. Long answer: all it takes is performing a simple hypothesis test, which is something you can in various ways, including the "restrict" command (see the Command Reference) Even longer answer: this is a very basic econometrics question. No offense, but this mailing list should be used for (a) questions about the software or (b) occasionally, discussion on how to perform some non-trivial econometric computation via gretl. Asking list members to answer the questions they normally give to their students as homework is not exactly the best way to make yourself popular. ------------------------------------------------------- Riccardo (Jack) Lucchetti Dipartimento di Scienze Economiche e Sociali (DiSES) Università Politecnica delle Marche (formerly known as Università di Ancona) r.lucchetti(a)univpm.it http://www2.econ.univpm.it/servizi/hpp/lucchetti -------------------------------------------------------