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ECN 202: Principles of Macroeconomics Nusrat Jahan Lecture-9. Aggregate Demand and Aggregate Supply. There is a very close relationship between Income, Consumption and Saving. Saving = Income-Consumption
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ECN 202: Principles of MacroeconomicsNusrat JahanLecture-9 Aggregate Demand and Aggregate Supply
There is a very close relationship between Income, Consumption and Saving. • Saving = Income-Consumption • To understand the way Consumption and Saving affects National Income we need to understand the following tools- • Consumption Function • Saving Function
Consumption Function: • Consumption Function is the relationship between Income and Consumption • Break-even Point- It is the level of income for which Income=Consumption • Non-Income Determinants of Consumption • Wealth • Expectation about Inflation • Real Interest Rate • Savings Function: • Savings Function is the relationship between Income and Saving. It can be derived from the Consumption Function
Marginal Propensity to Consume (MPC): The extra amount that people consume when they receive an extra dollar of disposable income. • Marginal Propensity to Save (MPS): The fraction of an extra dollar of disposable income that goes to extra saving. • MPC + MPS = 1 • Average Propensity to Consume (APC): The percentage of income spent. • Average Propensity to Save (APS): The percentage of Income saved. • APC + APS = 1
The Basic Model of Economic Fluctuations Aggregate Demand and Aggregate Supply • Two variables are used to develop a model to analyze the short-run fluctuations. • The economy’s output of goods and services measured by real GDP. • The overall price level measured by the CPI or the GDP deflator. • Economists use the model of aggregate demand and aggregate supply to explain short-run fluctuations in economic activity around its long-run trend.
The aggregate-demand curve shows the quantity of goods and services that households, firms, and the government want to buy at each price level. • The aggregate-supply curve shows the quantity of goods and services that firms choose to produce and sell at each price level. • The Aggregate Demand Curve • The four components of GDP (Y) contribute to the aggregate demand for goods and services. • Y = C + I + G + NX
Why the Aggregate Demand Curve might shift? • Shifts arising from • Consumption • Investment • Government Expenditure • Net Export • Why the Short-Run Aggregate-Supply Curve Might Shift • Labor • Capital • Natural Resources. • Technology. • Expected Price Level P AD’ AD AD” Y AS’ AS AS”
Two Causes of Economic Fluctuations • Shift in Aggregate Demand • Shift in Aggregate Supply