5. a. Fit a multiple regression model with infant birth weight as the response variable on infant sex, maternal weight gain during pregnancy, and maternal weight pre-pregnancy. b. Write out the equations for the predicted values, Y , for males and females. 6. a. Interpret the coefficients. NOTE: You do not need to interpret the intercept because it does not make sense in this context. b. Which variable(s) are significant? REMINDER: Per instructions, include test statistics 7. a. Next, add a term for the interaction between mom's weight gain during pregnancy and the sex of the infant to the model in question 5. b. Write out the equations for Y separately for males and females. c. Interpret the interaction effect. Is it statistically significant