HI, i've a simple quest as i can't find this solution anywhere. i've computed the betas of a regression and i want to use them on two different databases to see how does the intercept of these twos changes in the moment in which i consider specific already known betas for the factors.
i have found no ways to reach this goal, as with lm function i just can estimate all the coefficient, while i'm interested in computing a regression knowing already all coefficients except for alpha( the intercept).