The true quadratic regression function is e{y}=15+20x+3x2. the fitted linear regression function is y^=13+40x, for which e{b0}=10 and e{b1}=45. what are the bias and sampling error components of the mean squared error for xi=10 and xi=20?

With #! i’ve tried to figure it out but i can’t.

What is the value of x? enter your answer in the box. (cm)

Which approach to the theory-and-research cycle does the following sequence reflect: (1) specific observations suggest generalizations, (2) generalizations produce a tentative theory, (3) the theory is tested through the formation of hypotheses, and (4) hypotheses may provide suggestions for additional observations?