Refer to patient satisfaction problem 615 consider only the

Question

Refer to Patient satisfaction Problem 6.15. Consider only the first two predictors (Patient's age, X₁. an seventy of illness, X₁).

a. Fit a two-region regression tree. What is the first split point, and on which predictor is it based? What is SSE for the resulting two - region tree?

b. Find the second split point given the two-region tree in part (a). Is it is based on X₁ or X₂ ? What is SSE for the resulting three-region tree?

c. Find the third split point given the three-region tree in part (b). Is it based on X₁  or X₂. What is SSE for the resulting four-region tree?

d. Find the fourth split point given the four-region tree in part (c). Is it based on X ₁ or X₂? What is SSE for the resulting five-region tree?

e. Prepare a three-dimensional surface plot of the five-region tree obtained in part (d). What does this tree suggest about the relative importance of the two predictors?

f. Prepare a residual plot of ei versus  for the five-region tree in part (d). State your findings.

Problem:

The effects of five dose levels are to be studied in a completely randomized design, and 20 experimental units are available. Each dose level is to be assigned to four experimental units selected at random. Use a table of random digits or a random number generator to make an appropriate randomization of assignments.