We can find least-squares, best-fit polynomials of various degrees fitting a set of data. The larger the degree of the polynomial, the better fit we can get. Generally, it is desirable to fit data...

We can find least-squares, best-fit polynomials of various degrees fitting a set of data. The larger the degree of the polynomial, the better fit we can get. Generally, it is desirable to fit data with as simple a function as possible that does a good job. Investigate the best-fit polynomials of degree 1 through degree 6 for the data in Table 8.4 by running aidsdata and then using the MATLAB commands.

a. From the graphs these command produce, why does it seem most

reasonable to fit the data with a cubic?

b. From
SSEs computed by these commands, why does it seem reasonable

to fit the data with a cubic?