In the aforementioned study, Solow states: A scatter of q/A against k is shown in Chart 4. Considering the amount of a priori doctoring which the raw figures have undergone, the fit is remarkably tight. Except, that is, for the layer of points which are obviously too high. These maverick observations relate to the seven last years of the period, 1943–1949. From the way they lie almost exactly parallel to the main scatter, one is tempted to conclude that in 1943 the aggregate production function simply shifted.

a. Compute a scatter diagram of q/Aagainst k.

b. Estimate the four models you estimated in the previous problem including a dummy variable for the years 1943 to 1949. How do your results change? [Note: These results match those reported by Solow, although he did not report the coefficient on the dummy variable.]

c. Solow went on to surmise that, in fact, the data were fundamentally different in the years before 1943 than during and after. Use a Chow test to examine the difference in the two subperiods using your four functional forms. Note that with the dummy variable, you can do the test by introducing an interaction term between the dummy and whichever function of k appears in the regression. Use an F test to test the hypothesis.