. Use the data from Problem 11.1 to investigate running lines and running polynomial smoothers as described below: a. Smooth the data using a running-line smoother with symmetric nearest neighbors....

.
Use the data from Problem 11.1 to investigate running lines and running polynomial smoothers as described below:

a.
Smooth the data using a running-line smoother with symmetric nearest neighbors. Select a span of 2k
+ 1 for 1 ≤
k
≤ 11 chosen by cross-validation.

b.
Repeat this process for running local polynomial smoothers of degree 3 and 5; each time choose the optimal span using cross-validation over a suitable range for
k. (Hints: You may need to orthogonalize polynomial terms; also reduce the

polynomial degree as necessary for large spans near the edges of the data.)

c.
Comment on the quality and characteristics of the three smooths (local linear, cubic, and quintic).

d.
Does there appear to be a relationship between polynomial degree and optimal span?

e.
Comment on the three plots of CVRSS.