A sociologist wants to predict the birth weight(ounces) of b…

A sociologist wants to predict the birth weight(ounces) of babies based on the weight of the mother and if the mother smoked (0 if non-smoker and 1 if a smoker).  She used data from the San Francisco Bay area that included 1,236 mothers from 1960 – 1967.   Interpret “-8.67”.