4.19. (Sec. 4.2) Prove r has a monotone likelihood ratio for r > 0, P > 0 by proving her) = kN(r, PI)/kN(r, P2) is monotonically increasing for PI > P2' Here her) is a constant times O:~:;:~Oca prra)/(r::~Oca pfra). In the numerator of h'(r), show that the coefficient of r {3 is positive. '