You are interested in whether smoking potentially influences birth weight of babies. Suppose you estimate the following regression model 1: bweight; = do + acigs; + azfaminc; + ci (1) where "bweight" represents a child's weight at birth (in ounces), "cigs" is the number of cigarettes smoked per day by the mother while she was pregnant, and "faminc" is the total family income (in thousands of US dollars). a) Provide an intuition of the model above. How would you justify the selection of variables? Would you expect the estimated coefficients to be positiveegative, and why