Run a regression of Birthweight on the binary variable Smoker. Which of the following is true about the estimated slope and intercept? (Check all that apply) A. The estimated slope is the expected decrease in birth weight for every additional cigarette a mother smokes. B. The estimated intercept plus the estimated slope is the average birth weight for smoking mothers. C. The estimated intercept is the average birth weight for nonsmoking mothers. D. The estimated slope is the difference in average birth weight for smoking and nonsmoking mothers.