Given four data points (xi, yi) and the parameters for a cubic polynomial y(x) ˆ = ax3 + bx2 + cx + d, what will be the total error associated with the estimation function y(x) ˆ ? Can we place...

Given four data points (xi, yi) and the parameters for a cubic polynomial y(x) ˆ = ax3 + bx2 + cx + d, what will be the total error associated with the estimation function y(x) ˆ ? Can we place another data point (x,y) such that no additional error is incurred for the estimation function?