10. In each case below, determine whether, and under what assumptions, the stated relationship between Y and x can be represented in general linear model form such that the least squares estimator will provide a BLUE estimator of the b parameters.

(a) Yi ¼ exp Pn j¼1 xijbj þ ei

(b) Yi ¼ b0 þ b1 xi þ b2 x2 i þ ei

(c) Yi ¼ b0 Qk j¼1 xbj ij þ ei

(d) Yi ¼ x2i 1 þ ex1i bþei