The sacrifice ratio measures the percentage of annual real GDP that must be foregone to reduce inflation by one percentage point. Here, the inflation reduction is 4 percentage points (7% - 3% = 4%). With a sacrifice ratio of 5, the total output reduction is calculated as 5 multiplied by 4, which equals 20 percent. This represents the short-term cost of disinflation in terms of lost production.

The Phillips curve is a graphical representation that plots the inflation rate on the vertical axis and the unemployment rate on the horizontal axis. It illustrates the historical trade-off where lower levels of unemployment are associated with higher rates of inflation, serving as a fundamental tool for macroeconomic analysis and policy formulation.

The long-run Phillips curve is vertical at the natural rate of unemployment. Factors that increase structural unemployment, such as an increase in the minimum wage, can raise the natural rate of unemployment. This shift moves the long-run Phillips curve to the right. Other factors like changes in inflation expectations or aggregate demand typically cause movements along the curve or shifts in the short-run curve, rather than shifting the long-run vertical curve.

When expected inflation rises, workers demand higher nominal wages to maintain their purchasing power. This increase in production costs shifts the short-run Phillips curve upward. As a result, for any given level of unemployment, the economy now experiences higher inflation, making the trade-off between inflation and unemployment less favorable for policymakers.

The expectations-augmented Phillips curve posits that when actual inflation equals expected inflation, nominal wage growth aligns with expectations. At this point, the economy operates at the natural rate of unemployment, as there is no systematic surprise to workers or firms regarding price levels.

The short-run Phillips curve depicts the inverse trade-off between inflation and unemployment. When the economy experiences higher inflation, it is typically due to increased aggregate demand, which encourages firms to hire more workers, thereby lowering the unemployment rate. Conversely, lower inflation is associated with higher unemployment. This trade-off is a fundamental concept in short-run macroeconomic analysis, reflecting the responsiveness of the labor market to changes in price levels.

The Phillips curve illustrates an inverse relationship between inflation and unemployment in the short run. An increase in aggregate demand stimulates economic activity, leading to higher output and increased demand for labor. As firms hire more workers to meet the rising demand, the unemployment rate decreases, while inflation simultaneously rises.

When actual inflation is higher than expected, firms experience higher revenues while nominal wages remain fixed by prior contracts. This increases the real profitability of hiring, leading firms to expand production and employment. Consequently, the unemployment rate temporarily falls below the natural rate of unemployment as the economy moves along the short-run Phillips curve.

A monetary contraction reduces aggregate demand, which in the short run leads to lower inflation and higher unemployment as the economy moves along the short-run Phillips curve. In the long run, as expectations adjust downward, the economy moves toward a new equilibrium with lower inflation. Point H represents a state of lower inflation, consistent with the contractionary policy's impact on the price level and output gap.

A decrease in the price of foreign oil acts as a positive supply shock, reducing production costs for firms. This shift in aggregate supply allows for lower inflation at any given level of unemployment. Consequently, the short-run Phillips curve shifts downward, improving the trade-off between inflation and unemployment, as the economy can achieve lower unemployment rates without triggering the same level of inflationary pressure.