Consider once again the nutritional deficiency example and Model 4 from Chapter 8. In Section 9.6.5, the

Question:

Consider once again the nutritional deficiency example and Model 4 from Chapter 8. In Section 9.6.5, the parameter L = (β1 + β2) associated with one-unit increases in height and age was considered, and a 95% confidence interval for this linear function was computed. For this problem, we now consider the effect of a 3-inch height increase and a 2-year age increase.
a. What is the new value of L for a 3-inch increase in height and a 2-year increase in age?
b. What are the corresponding values of S2L and SL?
c. What is the 95% confidence interval for L.