Thank you very much for your answer. The model I am intended to describe is the relation between used tons salt on highroads (winter), where the depended variabel Y = used salt, a (dummy- snow or not), b = how many times the road temperatur is below 0, C = equals the temperatur, f= snow below zero degrees and g= smooth roads. Following the equation --> y= a*(b + c + f + g) + a. But after some reading, the proc model statement seems more convenient? proc model data=work1; parms a b c f g f; salt_tons=a*(b + c + f + g) + a; fit "Salt_tons"; run; But the following code doens't return any meaningful estimates, is the formular correct (expression)? Kind regards
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