Rework Problem 10.14, part a, but exclude the region information.
a. Comment on the difference in the models you have found. Is there indication that the region information substantially improves the model?
b. Calculate confidence intervals as mean quality for all points in the data set using the models from part a of this problem and Problem 10.14, part a. Based on this analysis, which model would you prefer?

Problem 10.14

Table B. 11 presents data on the quality of Pinot Noir wine.

Clarity, x Aroma, X Body, x3 Flavor, X4 Oakiness, xs Quality, y Region 1 3.3 2.8 1 4.4 4.9 1 3.9 5.3 3.9 2.6 3.1 3.5 4.8 3.1 5.6 5.1 5.5 15815 4.1 9.8 1 3.9 12.6 1 4.7 11.9 1 3.6 11.1 1 5.1 13.3 1 4.6 4.7 5 4.1 12.8 4.8 4.8 4.8 5.3 4.5 4.3 4.3 4.3 3.9 1 4.3 3.9 4.7 1 5.1 4.3 1 1 1 1 LUXEFFFFFF88-66---8-888- 4.5 0.5 3.3 5.4 4.3 839753 3.3 12.8 1 5.2 12 1 2.9 13.6 3 3.9 13.9 1 3.6 14.4 3 3.6 12.3 0.8 5.9 5.7 7 4.1 16.1 0.7 7.7 6.6 6.7 71 4.4 5.8 0.9 5.5 5.6 5.6 6.3 5.4 4.8 5 5.5 5.5 4.6 4.1 4.3 0.9 3.4 5 3.4 78685534 3.7 16.1 4.1 15.5 4.4 15.5 4.6 13.8 4.1 13.8 3.1 11.3 3.4 7.9 0.9 6.4 5.4 6.6 4.8 15.1 5.5 5.3 5.3 3.8 13.5 0.7 4.7 4.1 5 3.7 10.8 0.7 4.1 4 4.1 4 9.5 6 5.4 5.7 4.7 12.7 4.3. 4.6 4.7 4.9 11.6 3.9 4 5.1 5.1 11.7 5.1 4.9 5 5.1 11.9 3.9 4.4 5 4.4 10.8 4.5 3.7 2.9 3.9 8.5 5.2 4.3 5 6 10.7 0.8 4.2 3.8 3 4.7 9.1 3.3 3.5 4.3 4.5 12.1 6.8 6 5.2 14.9 2333mm m2332232-2222113 0.8 5 5.7 5.5 0.8 3.5 4.7 4.2 0.8 4.3 5.5 3.5 5251 4.8 13.5 3.3 12.2 5.8 10.3 0.8 5.2 4.8 5.7 3.5 13.2 1