The data are provided in the follow table.

Run y 1 2 3 4

1 81.94 1 5 35 6

2 52.38 1 10 50 8

3 54.62 1 15 65 10

4 84.92 2 5 50 10

5 78.93 2 10 65 6

6 36.47 2 15 35 8

7 67.79 3 5 65 8

8 43.96 3 10 35 10

9 42.85 3 15 50 6

a. Fit the first-order model, () = 0 + 11 + 2 2 + 3 3 + 4 4. Give the least squares prediction equation. (3) b. Conduct a test of overall model adequacy. Use = 0.10. (3) c. Interpret practically the value of 2 . (3) d. Find a 90% confidence interval for 3. (3) e. Conduct a test of 0: 4 = 0. What do you conclude? (3)