Response Surfaces & Optimization

Center points can detect aggregate curvature and estimate pure error. They cannot separately identify every quadratic term.

Fit locally, move in a promising direction, observe the response, and recenter. A local plane is not a global optimization model.

Solve for a stationary point, then classify it using curvature. A stationary point is not automatically a useful maximum.

Choose settings that achieve the desired mean while controlling sensitivity to noise. The best mean and the smallest variance may occur at different settings.