The generic formulation of a multiple regression model including age (x1=age in years), sex (x2= 1 if female, 0 if male), and smoking status (x3= 1 if smoker, and 0 if non-smoker) as predictors is as follows: LHS = intercept =+beta1_hat*x1 + beta2_hat*x2 + beta3_hat*x3 Where LHS = "left hand side", and intercept = beta_o_hat, or ln( lambda_hat[t] ). What comparison is being made by the slope beta3_hat? Smokers to non-smokers of the same age, but only among males. Smokers to non-smokers of the same sex and age. Smokers to non-smokers of the same age, but only among