Chi, You can add squares of variables using the "Add" menu (either the squares option or by defining a new variable). Then just include the squared variables in your regressor list with the others. PS Sent from my iPad On Aug 23, 2014, at 9:41 AM, "Chi B. Fule" <chifule@yahoo.co.uk<mailto:chifule@yahoo.co.uk>> wrote: Hi there, please may I receive assistance on how to regress a quadratic equation using cross-sectional data? Thanks in advance Chi _______________________________________________ Gretl-users mailing list Gretl-users@lists.wfu.edu<mailto:Gretl-users@lists.wfu.edu> http://lists.wfu.edu/mailman/listinfo/gretl-users