Abstract: For quadratic regression on [-1,1], exact n-point A-optimal designs are determined when n≡0, 1, 3 (mod 4). Some conjectures for the exact A-optimal designs when n≡2 (mod 4) are stated. For the case [-a,a],a>0 , the properties of exact A-optimal designs are discussed on grounds of an intensive numerical study.
Key words and phrases: A-optimal, exact design, quadratic regression.