Introductory Econometrics 4th Edition by Jeffrey Wooldridge

تمرين 8

Use CRIME3.RAW for this exercise.
(i) In the model of Example, test the hypothesis H 0 : 1 = 2. (Hint: Define 1 = 1 - 2 and write 1 in terms of 1 and ft. Substitute this into the equation and then rearrange. Do a t test on 1.)
(ii) If ft = ft, show that the differenced equation can be written as
Alog(crimei) = 0 + 1 avgclr i + u i , where 1 = 2 1 and avgclr. = (clrprc 4-1 + clrprc 4-2 )/2 is the average clear-up percentage over the previous two years.
(iii) Estimate the equation from part (ii). Compare the adjusted R-squared with that in (13.22). Which model would you finally use