a. ) The GNP gap is the difference between actual GNP and potential GNP. Okun's law suggests a GNP gap of -2% for every 1% that the unemployment rate exceeds its natural rate. In this case, the GNP gap is (9.0 – 5) x -2 = -8%.
The size of GNP gap in percentage point terms is -8%
b)A GDP gap of -8% implies that $500 x .09 = $45 billion of output is being foregone because of cyclical unemployment.