Then =1-91=1(3+:2)(3+2n 可=-1-3)=1(4-+2)(1-2+a With 1 0 O: Thus, in equilibrium, we must have ai=.2. In fact, the two firms must sit in the middle By Proposition 2.1, Pi=p?=c Discussion
Fixed Effects estimation When there is an observed fixed effect. an alternative to first differences is fixed effects estimation Consider the average over time of y Bx1+…+Bxik+a1+l The average of a, will be ai so if you subtract the mean. a will be differenced out just as when doing first differences Economics 20- Prof anderson
I．Choose the Correct Answer 1. A disturbance can be written x b xt b t a y(x,t) (e e e ) 2 2 −( / ) 2 / − = . This disturbance is （ D ） (A) Not a traveling wave. (B) A traveling wave with speed v = a. (C) A traveling wave with speed v = a/b. (D) A traveling wave with speed v = b
I. Choose the Correct Answer 1. A particle moves with position given by r ti j = 3 ˆ + 4 ˆ v , where r v is measured in meters when t is measured in seconds. For each of the following, consider only t > 0. The magnitude of the angular momentum of this particle about the origin is （ B ）
