How do I solve this?

2. (16 points) As an economist, you collect data on births to women in Alaska. Two variables of interest are the dependent variable, infant birth weight in ounces (bwght), and an explanatory variable, average number of cigarettes the mother smoked per day during pregnancy (cigs). The following simple regression is estimated using data on *=14,000 births: bught=119.77-0.514cigs (a) Interpret the intercept clearly (3 points). (b) Interpret the coefficient on cigs clearly (3 points). (c) To predict a birth weight of 125 ounces, what would cigs have to be? Does it make sense? Explain clearly (4 points) (d) What is the predicted birth weight when cigs-20 (one pack per day)? (3 points) (e) Agree or disagree with the following statement, and explain clearly: "The sum, and therefore the sample average of the OLS errors, is zero." (3 points)