Consider the following table. 1.6 2.1 2.4 4.7 XL Y₁ 3.0 3.65 4.25 12.147 14.436 16.318 17.743 5.6 20.416 6.841 8.794 9.921 a) Construct the least squares polynomial of degree 4 and compute the error. b) Construct the least squares approximation of the form be ax, and compute the error.