Table 17.4 reports interprovincial migration in Canada for the period 1966 to 1971. Also shown in this table are the 1966 and 1971 provincial populations. Table 17.5 gives road distances among the major cities in the 10 provinces. Averaging the 1966 and 1971 population figures, fit the gravity model of migration (Equation 17.3 on page 512) to the interprovincial migration data. Display the residuals from the fitted model in a 10 · 10 table. Can you account for the pattern of residuals? How might the model be modified to provide a more satisfactory fit to the data? (Why can’t we simply use dummy regressors to incorporate province effects for the source and destination provinces?)