More on quadratic models o Suppose that the coefficient on x is negative and the coefficient on x2 is positive e Then y is decreasing in x at first, but will eventually turn around and be increasing in x For,<Oand B2>0 the turning point will be at x=B /22 Which IS the same as when B, >0 and d B <0 Economics 20- Prof anderson 10Economics 20 - Prof. Anderson 10 More on Quadratic Models Suppose that the coefficient on x is negative and the coefficient on x 2 is positive Then y is decreasing in x at first, but will eventually turn around and be increasing in x ( ) 0 ˆ 0 and ˆ the same as when , which is ˆ 2 ˆ will be at 0 the turning point ˆ 0 and ˆ For 1 2 1 2 * 1 2   =   b b b b b b x