(2)Restricted least squares(RLs) inY=B1+B2×21+B×31+u1 If we put any restrictions on the parameters such as B.=2 or B.+ B.=1. we use RLs method to estimate The steps of RLS: transform the data to take into account the restrictions suggested by the relevant theory apply the least squares method (ols).（2）Restricted least squares(RLS) In Yi=B1+B2X2i+B3X3i+ui If we put any restrictions on the parameters, such as B2 =2, or B2+ B3 =1, we use RLS method to estimate. The steps of RLS: ·transform the data to take into account the restrictions suggested by the relevant theory, ·apply the least squares method (OLS)