Hypothesis testing If F>F refuse H the restriction(s) imposed by the theory is not valid ( statistically speaking), reject the restricted least squares regression. use the standard ols method If F<F, accept H the given restriction is valid, the rls regression is preferred to ULSHypothesis testing: If F>Fc , refuse H0 , the restriction(s) imposed by the theory is not valid （statistically speaking）, reject the restricted least squares regression , use the standard OLS method. If F<Fc , accept H0 , the given restriction is valid, the RLS regression is preferred to ULS