1、AGGREGATE SUPPLYANDAGGREGATE DEMAND,Objectives,總供給 aggregate supply 總體經(jīng)濟(jì)的長期、短期 總需求 aggregate demand 總體經(jīng)濟(jì)的均衡macroeconomic equilibrium 經(jīng)濟(jì)成長、通貨膨脹與產(chǎn)出水準(zhǔn)的關(guān)係 economic growth, inflation, 景氣循環(huán)的產(chǎn)生 business cycles,Production and Prices,What forces bring persistent and rapid expansion of real GDP? What causes i

2、nflation? Why do we have business cycles? How do policy actions by the government and the Federal Reserve affect output and prices?,總供給Aggregate Supply,總供給(生產(chǎn))成長的速度受 : 勞動 The quantity of labor (L ) 資本 The quantity of capital (K ) 技術(shù) The state of technology (T )影響 The aggregate production function sh

3、ows how quantity of real GDP supplied, Y, depends on labor, capital, and technology.,Aggregate Supply,The aggregate production function is written as the equation: Y = F(L, K, T ). The larger is L, K, or T, the greater is Y.,勞動的數(shù)量受實(shí)質(zhì)工資影響,At any given time, the quantity of capital and the state of te

4、chnology are fixed but the quantity of labor can vary. The higher the real wage rate, the smaller is the quantity of labor demanded and the greater is the quantity of labor supplied. The wage rate that makes the quantity of labor demanded equal to the quantity supplied is the equilibrium wage rate a

5、nd at that wage the level of employment is the natural rate of unemployment.,Unemployment and Full Employment,the labor market flows between the different states.,Long-Run short-RunAggregate Supply,總體經(jīng)濟(jì)供給的長短期區(qū)別在於: 勞動 The quantity of labor (L ) 資本 The quantity of capital (K ) 技術(shù) The state of technolo

6、gy (T ) 是否能改變,Long-Run short-RunAggregate Supply,Long-Run Aggregate Supply The macroeconomic long run is a time frame that is sufficiently long for all adjustments to be made so that real GDP equals potential GDP and there is full employment. The long-run aggregate supply curve (LAS) is the relation

7、ship between the quantity of real GDP supplied and the price level when real GDP equals potential GDP. potential GDP: 充分就業(yè)時的產(chǎn)出水準(zhǔn),Long-Run Aggregate Supply,The LAS curve is vertical because potential GDP is independent of the price level. 充分就業(yè)時的產(chǎn)出水準(zhǔn)不受價格水準(zhǔn)的影響,Long-Run Aggregate Supply,Along the LAS cu

8、rve relative prices and the real wage rate remain constant 相對價格與實(shí)質(zhì)工資不變 GDP at the full employment level,Short-Run Aggregate Supply,The macroeconomic short run is a period during which real GDP has fallen below or risen above potential GDP. 短期間GDP可以偏離充分就業(yè)時的產(chǎn)出水準(zhǔn) At the same time, the unemployment rate

9、 has risen above or fallen below the natural unemployment rate. The short-run aggregate supply curve (SAS) is the relationship between the quantity of real GDP supplied and the price level in the short run when the money wage rate, the prices of other resources, and potential GDP remain constant.,Sh

10、ort-Run Aggregate Supply,Along the SAS curve, rise in the price level with no change in the money wage rate and other input prices increases the quantity of real GDP suppliedthe SAS curve is upward sloping. 短期間名目工資和要素價格,相對於產(chǎn)品(一般物價水準(zhǔn)),來不及變動 例如工資每年調(diào)整1次,The SAS curve is upward sloping,a rise in the pri

11、ce level with no change in costs induces firms to bear a higher marginal cost and increase production; 產(chǎn)品(一般物價水準(zhǔn))上升而名目工資和要素價格來不及變動相當(dāng)於實(shí)質(zhì)工資下降使供給者能承受較高的名目工資及增加生產(chǎn) and a fall in the price level with no change in costs induces firms to decrease production to lower marginal cost.,The SAS curve,Along the SA

12、S curve, real GDP might be above potential GDP or below potential GDP. GDP & price level can vary, but input prices stay unchanged.,Movement along the LAS Curves,A change in the price level with an equal percentage change in the money wage rate causes a movement along the LAS curve.,Movement along t

13、he SAS Curves,A change in the price level with no change in the money wage rate causes a movement along the SAS curve. 沒有名目工資配合上升的物價波動幅度不及 有名目工資配合上升的物價波動幅度,SAS LAS的價與量,SAS curve:產(chǎn)品(一般物價水準(zhǔn))上升而名目工資和要素價格來不及變動 但GDP會因相對價格的原因短暫衝高或滑落 LAS curve:產(chǎn)品(一般物價水準(zhǔn))上升而名目工資和要素價格等量變動 但GDP不會偏離充分就業(yè)時的產(chǎn)出水準(zhǔn),總體的價與量,一般物價水準(zhǔn)易因需求

14、而快速改變 但名目工資和要素價格來不及變動 總產(chǎn)量GDP會因相對價格的原因短暫衝高或滑落 但充分就業(yè)時的產(chǎn)出水準(zhǔn)只會因充分就業(yè)勞動 資本 技術(shù) 而改變,Changes in Aggregate Supply,When potential GDP increases, both the LAS and SAS curves shift rightward. 充分就業(yè)時的產(chǎn)出水準(zhǔn)因充分就業(yè)勞動 資本 技術(shù) 而改變時LAS and SAS curves以相同幅度改變,Potential GDP changes, for three reasons:,Change in the full-employ

15、ment quantity of labor Change in the quantity of capital (physical or human) Advance in technology,Aggregate Supply increases,當(dāng)充分就業(yè)時的產(chǎn)出水準(zhǔn)因充分就業(yè)勞動 資本 技術(shù) 而改變時LAS and SAS curves以相同幅度改變,money wage rate & aggregate supply,A rise in the money wage rate decreases short-run aggregate supply and shifts the SA

16、S curve leftward. 名目工資上升使SAS 左移 物價上升 但總供給不變,Aggregate Demand,The quantity of real GDP demanded, Y, is the total amount of final goods and services produced in a country that people, businesses, governments, and foreigners plan to buy. This quantity is the sum of consumption expenditures, C, investme

17、nt, I, government purchases, G, and net exports, X M. That is: Y = C + I + G + X M,Aggregate Demand,Buying plans depend on many factors and some of the main ones are: The price level Expectations Fiscal and monetary policy The world economy,Aggregate Demand,The AD curve slopes downward for two reaso

18、ns: A wealth effect Substitution effects,Wealth effect 財富效果,A fall in the price level, other things remaining the same, increases the quantity of real wealth. With more real wealth, people decrease saving and increase spending, so the quantity of real GDP demanded increases. Similarly, a rise in the

19、 price level, other things remaining the same, decreases the quantity of real wealth (money, bonds, stocks, etc.) To restore their real wealth, people increase saving and decrease spending, so the quantity of real GDP demanded decreases.,Intertemporal substitution effect代間替代效果,A rise in the price le

20、vel, other things remaining the same, decreases the real value of money and raises the interest rate. 物價上升使貨幣價值降低 要求較高利率 Faced with a higher interest rate, people try to borrow and spend less so the quantity of real GDP demanded decreases. Similarly, a fall in the price level increases the real valu

21、e of money and lowers the interest rate. Faced with a lower interest rate, people borrow and spend more so the quantity of real GDP demanded increases.,International substitution effect跨國替代效果,A rise in the price level, other things remaining the same, increases the price of domestic goods relative t

22、o foreign goods, so imports increase and exports decrease, which decreases the quantity of real GDP demanded. Similarly, a fall in the price level, other things remaining the same, decreases the price of domestic goods relative to foreign goods, so imports decrease and exports increase, which increa

23、ses the quantity of real GDP demanded.,Changes in Aggregate Demand,A change in any influence on buying plans other than the price level changes aggregate demand. The main influences on aggregate demand are: Expectations Fiscal and monetary policy The world economy,Expectations預(yù)期,Expectations about f

24、uture income, future inflation, and future profits change aggregate demand. Increases in expected future income increase peoples consumption today, and increases aggregate demand. A rise in the expected inflation rate makes buying goods cheaper today and increases aggregate demand. An increase in ex

25、pected future profits boosts firms investment, which increases aggregate demand.,Fiscal policy財政政策,Fiscal policy is the governments attempt to influence economic activity by changing its taxes, spending, deficit, and debt policies. A tax cut or an increase in transfer payments increases households d

26、isposable incomeaggregate income minus taxes plus transfer payments. An increase in disposable income increases consumption expenditure and increases aggregate demand.減稅或提高移轉(zhuǎn)性支出 增加總需求,Monetary policy 貨幣政策,Because government purchases of goods and services are one component of aggregate demand, an in

27、crease in government purchases increases aggregate demand. Monetary policy is changes in the interest rate and quantity of money.利率 貨幣數(shù)量 An increase in the quantity of money increases buying power and increases aggregate demand.貨幣數(shù)量增加總需求增加 A cut in the interest rate increases expenditure and increas

28、es aggregate demand.利率降低總需求增加,Aggregate Demand,The world economy influences aggregate demand in two ways: A fall in the foreign exchange rate 匯率lowers the price of domestic goods and services relative to foreign goods and services, increases exports, decreases imports, and increases aggregate demand

29、. 本國貨幣貶值 使產(chǎn)品相對便宜 出口增加 進(jìn)口減少 需求增加 An increase in foreign income increases the demand for U.S. exports and increases aggregate demand.,Aggregate Demand,When aggregate demand increases, the AD curve shifts rightward and when aggregate demand decreases, the AD curve shifts leftward.,Macroeconomic Equilib

30、rium,Short-Run Macroeconomic Equilibrium Short-run macroeconomic equilibrium 短期均衡 occurs when the quantity of real GDP demanded equals the quantity of real GDP supplied at the point of intersection of the AD curve and the SAS curve.,Macroeconomic Equilibrium,If real GDP is below equilibrium GDP, fir

31、ms increase production and raise prices, and if real GDP is above equilibrium GDP, firms decrease production and lower prices.,Short-run Macroeconomic Equilibrium,In short-run equilibrium, real GDP can be greater than or less than potential GDP. 短期均衡GDP可能高於或低於充分就業(yè)水準(zhǔn),Macroeconomic Equilibrium,Long-Ru

32、n Macroeconomic Equilibrium Long-run macroeconomic equilibrium occurs when real GDP equals potential GDPwhen the economy is on its LAS curve. 長期均衡GDP等於充分就業(yè)水準(zhǔn),Macroeconomic Equilibrium,Long-run equilibrium occurs where the AD and LAS curves intersect and results when the money wage has adjusted to pu

33、t the SAS curve through the long-run equilibrium point.,Economic growth & Inflation,Economic growth occurs because the quantity of labor grows, capital is accumulated, and technology advances, all of which increase potential GDP and bring a rightward shift of the LAS curve.,Macroeconomic Equilibrium

34、,Inflation occurs because the quantity of money grows faster than potential GDP, which increases aggregate demand by more than long-run aggregate supply. The AD curve shifts rightward faster than the rightward shift of the LAS curve.,The Business Cycle,The business cycle occurs because aggregate dem

35、and and the short-run aggregate supply fluctuate but the money wage rate does not change rapidly enough to keep real GDP at potential GDP.,A below full-employment equilibrium is an equilibrium in which potential GDP exceeds real GDP. The amount by which potential GDP exceeds real GDP is called a rec

36、essionary gap. 緊縮缺口:充分就業(yè)產(chǎn)出大於均衡所得的部分,A long-run equilibrium is an equilibrium in which potential GDP equals real GDP.,An above full-employment equilibrium is an equilibrium in which real GDP exceeds potential GDP. The amount by which real GDP exceeds potential GDP is called an inflationary gap. 膨脹缺口:

37、充分就業(yè)產(chǎn)出小於均衡所得的部分,景氣循環(huán)的產(chǎn)生 as the economy moves from one type of short-run equilibrium to another, real GDP fluctuates around potential GDP in a business cycle. 短期實(shí)際產(chǎn)出因AD SAS而定，但可能大於或小於充分就業(yè)產(chǎn)出，使物價水準(zhǔn)與名目工資偏離均衡，致使實(shí)際產(chǎn)出持續(xù)調(diào)整,Fluctuations in Aggregate Demand,Starting at long-run equilibrium, an increase in aggregate demand shifts the AD curve rightward. Firms increase production and