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Study Notes BS Economics At GCU University Lahore.

Principles of Economics (ECON-1102) – Comprehensive Study Notes

Course Overview

PART 1: Introduction to Economics

1.1 What is Economics?

Economics is the social science that studies the choices individuals, businesses, governments, and societies make as they cope with scarcity and the incentives that influence and reconcile those choices .

Scarcity: Limited resources (land, labor, capital, entrepreneurship) relative to unlimited human wants → forces trade-offs.

Two Major Branches of Economics:

1.2 The 10 Principles of Economics (Mankiw)

1.3 The Economic Problem: Scarcity and Choice

Factors of Production (Resources):

Production Possibilities Frontier (PPF): Graph showing maximum combinations of two goods an economy can produce given fixed resources and technology.

Quantity of Y (Capital goods)
|
|   A (inside = inefficient/unemployed resources)
|      B (on curve = efficient)
|        \
|         \
|          \ (C = unattainable given current resources/technology)
|___________ Quantity of X (Consumer goods)

Key PPF Concepts:

• Points on curve: Efficient (full employment, productive efficiency)

• Points inside curve: Inefficient (unemployment, idle resources)

• Points outside curve: Unattainable with current resources and technology (economic growth shifts PPF outward)

• Slope = Opportunity cost (amount of Y given up to produce one more unit of X)

• Increasing opportunity cost: PPF is bowed outward (resources not equally suited to both goods)

PART 2: Microeconomics

2.1 Demand

Demand: Quantity of a good buyers are willing and able to purchase at various prices during a given period.

Law of Demand: Price ↑ → Quantity Demanded ↓ (inverse relationship), ceteris paribus.

Reasons for Law of Demand:

• Substitution effect: Higher price makes good relatively more expensive → buyers switch to substitutes

• Income effect: Higher price reduces real purchasing power (feeling poorer) → reduce quantity demanded

Demand Schedule and Curve:

Downward sloping curve.

Change in Quantity Demanded vs. Change in Demand:

Non-Price Determinants of Demand (Shift Factors – memorization essential):

2.2 Supply

Supply: Quantity of a good sellers are willing and able to sell at various prices during a given period.

Law of Supply: Price ↑ → Quantity Supplied ↑ (direct relationship), ceteris paribus.

Reason: Higher prices increase profit incentive, encourage existing firms to produce more and new firms to enter.

Supply Schedule and Curve:

Upward sloping curve.

Change in Quantity Supplied vs. Change in Supply:

Non-Price Determinants of Supply (Shift Factors):

2.3 Market Equilibrium

Equilibrium: Quantity demanded = Quantity supplied (no tendency to change).

Market Adjustment to Disequilibrium:

• Surplus (excess supply): Qs > Qd → price falls (sellers compete) → quantity demanded increases (law of demand), quantity supplied decreases (law of supply) → equilibrium restored

• Shortage (excess demand): Qd > Qs → price rises (buyers compete) → quantity demanded decreases, quantity supplied increases → equilibrium restored

2.4 Effects of Demand and Supply Shifts

When both shift simultaneously (memorization):

Example: Technological advance (supply ↑) + increased consumer income for normal good (demand ↑). Quantity increases unambiguously; price change depends on magnitude of shifts.

2.5 Elasticity

Elasticity: Measure of responsiveness of quantity demanded or supplied to a change in one of its determinants.

2.5.1 Price Elasticity of Demand (Ed)

Ed=% change in quantity demanded% change in price=ΔQ/QΔP/PEd​=% change in price% change in quantity demanded​=ΔP/PΔQ/Q​

Interpretation (absolute value):

Midpoint (Arc) Formula (to avoid direction bias):

Ed=(Q2−Q1)/[(Q1+Q2)/2](P2−P1)/[(P1+P2)/2]Ed​=(P2​−P1​)/[(P1​+P2​)/2](Q2​−Q1​)/[(Q1​+Q2​)/2]​

Determinants of Price Elasticity of Demand (memorization):

1. Availability of close substitutes: More substitutes → more elastic

2. Necessity vs. luxury: Necessities (inelastic); Luxuries (elastic)

3. Definition of market: Narrow markets (more elastic) vs. broad markets (less elastic)

4. Time horizon: Longer time → more elastic (consumers find substitutes or adjust behavior)

Elasticity and Total Revenue (Price × Quantity):

Example: If demand for gasoline is inelastic, an increase in price increases total revenue (gas stations).

2.5.2 Income Elasticity of Demand (Ei)

Ei=% change in quantity demanded% change in incomeEi​=% change in income% change in quantity demanded​

2.5.3 Cross-Price Elasticity of Demand (Exy)

Exy=% change in quantity demanded of good X% change in price of good YExy​=% change in price of good Y% change in quantity demanded of good X​

2.5.4 Price Elasticity of Supply (Es)

Es=% change in quantity supplied% change in priceEs​=% change in price% change in quantity supplied​

Determinants of supply elasticity:

• Time period: Longer time → more elastic (firms adjust production capacity)

• Availability of inputs (raw materials, labor)

• Flexibility of production process

PART 3: Markets and Welfare

3.1 Consumer Surplus, Producer Surplus, and Efficiency

Efficiency of Competitive Markets: In perfectly competitive markets without externalities, the equilibrium price and quantity maximize total surplus (Adam Smith’s “invisible hand”).

3.2 Price Controls

Price Ceiling: Legal maximum price (set below equilibrium to help buyers).

Price Floor: Legal minimum price (set above equilibrium to help sellers).

3.3 Taxes and Subsidies

Tax Incidence: Distribution of tax burden between buyers and sellers.

Key Principle: Tax burden falls on the side of the market that is less elastic (more inelastic) → cannot easily escape by changing behavior.

Deadweight Loss (DWL): Loss in total surplus due to market distortion (tax, subsidy, price control, monopoly). Represents trades that do not occur (mutually beneficial) because of the policy/incentive structure.

PART 4: Market Structures

4.1 Four Types of Markets

4.2 Perfect Competition

Characteristics:

• Many buyers and sellers (no individual can influence market price)

• Homogeneous (identical) product

• Free entry and exit (no barriers)

• Perfect information (consumers know prices; firms know technology)

Firm’s Demand Curve: Perfectly elastic (horizontal) at market price.

Profit Maximization Rule for ALL Firms: MR = MC (Marginal Revenue = Marginal Cost)

In Perfect Competition:

• MR = P (firm can sell all output at market price; price = marginal revenue)

• Profit max when P = MC

Short-Run Equilibrium:

• If P > ATC → Economic profit

• If P < AVC → Shut down (loss > fixed cost)

• In between AVC and ATC → Operating at loss (covers variable cost + part of fixed cost)

Long-Run Equilibrium in Perfect Competition:

• Economic profit attracts entry (new firms enter)

• Entry → Supply shifts right → Price falls until P = ATC = MC (zero economic profit)

• Long-run supply curve: horizontal at minimum of ATC (constant cost industry)

4.3 Monopoly

Barriers to Entry:

• Natural monopoly: Economies of scale (one firm can supply entire market at lower cost than multiple firms) → utilities (water, electricity)

• Legal monopoly: Patents (temporary 20 years), copyrights, government franchise

• Control of essential resource (e.g., DeBeers diamonds historically)

Monopoly Pricing and Output:

• Faces downward-sloping demand curve (must lower price to sell more)

• MR lies below demand curve (MR < P)

• Profit max: MR = MC → determines Qm

• Price (Pm) determined from demand curve at that Qm

• Pm > MC → markup over marginal cost

• Economic profit possible in long run (barriers to entry)

Deadweight Loss from Monopoly: Higher price, lower quantity compared to perfect competition → total surplus reduced (consumer surplus transfers to producer, plus DWL from reduced output).

4.4 Oligopoly and Game Theory

Characteristics:

• Few firms → strategic interaction (each firm’s decisions affect rivals)

• Products may be homogeneous (steel) or differentiated (automobiles)

• High barriers to entry

Game Theory Concepts:

• Prisoner’s Dilemma: Individual rationality leads to collectively worse outcome

• Dominant strategy: Best strategy regardless of rival’s choice

• Nash equilibrium: Each player chooses best strategy given strategies of others; no incentive to deviate unilaterally

Collusion vs. Competition:

• Collusion: Firms cooperate to act like monopolist (restrict output, raise price) → illegal in most countries (antitrust laws)

• Cartel: Formal collusion (e.g., OPEC in oil)

• Tacit collusion (price leadership): One firm signals price changes, others follow

PART 5: Macroeconomics

5.1 Measuring National Income (GDP)

Gross Domestic Product (GDP): Market value of all final goods and services produced within a country during a specific period .

5.1.1 Two Approaches to Calculate GDP

Expenditure Approach (Y = C + I + G + (X – M)):

Income Approach: GDP = Wages + Rent + Interest + Profit + Statistical adjustments (indirect taxes minus subsidies, depreciation).

Nominal GDP vs. Real GDP:

5.2 Inflation

Inflation: Sustained increase in general price level.

Deflation: Sustained decrease in general price level (→ reduced spending, debt burdens rise).

Consumer Price Index (CPI): Measures cost of fixed basket of consumer goods (households).

CPI=Cost of basket in current yearCost of basket in base year×100CPI=Cost of basket in base yearCost of basket in current year​×100

Inflation Rate (CPI-based):

Inflation rate=CPIcurrent−CPIpreviousCPIprevious×100Inflation rate=CPIprevious​CPIcurrent​−CPIprevious​​×100

Problems with CPI (biases upward):

• Substitution bias (consumers switch to cheaper goods when relative prices change; fixed basket ignores substitution)

• New goods bias (new products not included immediately)

• Quality change bias (quality improvements not fully accounted for)

Real vs. Nominal Variables:

Costs of Inflation:

• Menu costs (cost of changing prices – printing menus, price tags, catalogs)

• Shoe-leather costs (cost of reducing money holdings – more trips to bank)

• Unexpected redistribution of wealth (creditors hurt, debtors benefit from unexpected inflation; fixed interest rate loans redistribute)

• Tax distortions (bracket creep pushes taxpayers into higher brackets)

• Uncertainty → lower investment

5.3 Unemployment

Labor Force: Employed + Unemployed (actively seeking work).

Unemployment Rate (U-3 official rate):

Unemployment rate=Number of unemployedLabor force×100Unemployment rate=Labor forceNumber of unemployed​×100

Labor Force Participation Rate:

LFPR=Labor forceWorking-age population (civilian non-institutionalized population)×100LFPR=Working-age population (civilian non-institutionalized population)Labor force​×100

Types of Unemployment:

Natural Rate of Unemployment: Frictional + Structural (full employment level; cyclical unemployment = zero). Does not mean zero unemployment; means economy at potential output.

5.4 Business Cycle

Phases of Business Cycle:

PART 6: Macroeconomic Policy

6.1 Fiscal Policy (Government Spending and Taxation)

Expansionary Fiscal Policy: Used during recession (increase G, decrease T, or both) → aggregate demand (AD) shifts right → increases output; may increase price level (demand-pull inflation) and government budget deficit.

Contractionary Fiscal Policy: Used to combat inflation during expansion (decrease G, increase T, or both) → AD shifts left → reduces inflationary pressure; may increase unemployment.

Multiplier Effect: Initial change in spending (G or autonomous C or I) leads to larger change in aggregate output (GDP) through successive rounds of spending.

Spending Multiplier=11−MPCSpending Multiplier=1−MPC1​

where MPC = marginal propensity to consume (fraction of additional income spent).

Tax Multiplier: Smaller than spending multiplier in magnitude (absolute value). Tax cut increases disposable income, part spent (MPC).

Tax Multiplier=−MPC×Spending Multiplier=−MPC1−MPCTax Multiplier=−MPC×Spending Multiplier=−1−MPCMPC​

Automatic Stabilizers: Mechanisms that reduce cyclical fluctuations without discretionary policy (tax revenues fall during recession automatically → reduces net tax revenue → cushions AD decline; unemployment benefits increase automatically during recession).

6.2 Monetary Policy (Central Bank – Federal Reserve, ECB, SBP)

Functions of Money:

1. Medium of exchange (facilitates transactions)

2. Unit of account (common measure of value; prices denominated in currency)

3. Store of value (transfers purchasing power from present to future; inflation erodes value)

Measures of Money Supply:

Fractional Reserve Banking: Banks keep only fraction of deposits as reserves (required reserve ratio set by central bank). The rest can be loaned out → money creation.

Money Multiplier:

Money multiplier=1Required reserve ratio (rr)Money multiplier=Required reserve ratio (rr)1​

Monetary Policy Tools:

Transmission Mechanism: Money supply ↑ → interest rate ↓ → investment and consumption ↑ → aggregate demand ↑ → GDP ↑ (and possibly price level ↑).

6.3 Aggregate Demand and Aggregate Supply (AD-AS Model)

Aggregate Demand (AD): Total quantity of output (real GDP) demanded at various price levels, ceteris paribus. Downward-sloping.

Why AD slopes downward (for macroeconomy, not micro reasons like substitution):

• Wealth effect (P ↓ → real wealth ↑ → consumption ↑ → Y ↑)

• Interest rate effect (P ↓ → households need less money to buy goods → lend excess → interest rate ↓ → investment ↑ → Y ↑)

• International trade effect (P ↓ (relative to foreign countries) → exports ↑, imports ↓ → net exports ↑ → Y ↑)

Aggregate Supply (SRAS – Short Run): Upward-sloping (as price level rises, firms increase output due to sticky wages/prices, profit margins expand).

Long-Run Aggregate Supply (LRAS): Vertical at potential output (natural rate of output, full employment Y). Determined by quantity/quality of resources, technology, institutions (not price level).

Shifts in AD:

Shifts in SRAS:

AD-AS Equilibrium Analysis:

Summary Tables

Microeconomics Summary

Macroeconomics Summary

Glossary of Key Terms

Example Problems

Problem 1: Demand equation: Qd = 100 – 2P; Supply equation: Qs = –20 + 4P. Find equilibrium.

Solution: Set Qd = Qs → 100 – 2P = –20 + 4P → 100 + 20 = 4P + 2P → 120 = 6P → P = $20.
Q = 100 – 2(20) = 100 – 40 = 60 units (or Q = –20 + 80 = 60).

Problem 2: Price rises from $4to$5. Quantity demanded falls from 80 to 60. Calculate Ed using midpoint method and interpret.

Solution: %ΔQ = (60 – 80) / [(80+60)/2] = (–20) / 70 = –0.2857 (28.57%).
%ΔP = (5 – 4) / [(4+5)/2] = 1 / 4.5 = 0.2222 (22.22%).
Ed = 0.2857 / 0.2222 = 1.2857 (inelastic? Wait, 0.2857/0.2222 = 1.2857 >1 → elastic actually.)
(Recheck: Absolute value 1.29 >1 → elastic. Demand is price sensitive.)

Interpret: 1% increase in price → 1.29% decrease in quantity demanded.

Problem 3: Basket for base year (2020): 10 loaves bread @ $2and5gallonsmilk@$3 → cost = 20+15=35. Current year (2025): same basket costs: bread @ $2.50\to 25;milk@$4 → 20; total = 45. CPI = (45/35)×100 = 128.6. Inflation rate = (128.6 – 100)/100 × 100 = 28.6%.

Recommended Textbooks

1. Mankiw, N. G. (2024). Principles of Economics (10th ed.). Cengage. (Standard introductory text, accessible and well-organized.)

2. Tucker, I. B. (2022). Economics for Today (11th ed.). Cengage. (Concise.)

3. Krugman, P., & Wells, R. (2021). Economics (6th ed.). Worth Publishers. (Modern approach with emphasis on real-world examples.)

*These notes provide a comprehensive foundation for ECON-1102 Principles of Economics. Mastery requires consistent practice: solving elasticity problems, drawing and shifting AD-AS diagrams, calculating GDP/CPI/unemployment rates.*

Study Notes: Principles of Microeconomics (ECON-1202)

1. What is Microeconomics?

Microeconomics is the branch of economics that studies the behavior of individual economic units – households, firms, and markets – and how they make decisions regarding the allocation of scarce resources.

Microeconomics vs. Macroeconomics

Core Economic Concepts

Fundamental economic problem: How to allocate scarce resources to satisfy unlimited wants.

2. The Production Possibilities Frontier (PPF)

The PPF is a curve showing the maximum combinations of two goods an economy can produce given fixed resources and technology.

Shape of the PPF

Key Concepts from PPF

Example PPF: Guns vs. Butter

Guns
  |\
  | \
  |  \  (Increasing opportunity cost)
  |   \
  |    \
  +-----→ Butter

3. Demand, Supply & Market Equilibrium

Demand

Demand = Quantity of a good buyers are willing and able to purchase at various prices.

Law of Demand: Price ↑ → Quantity demanded ↓ (inverse relationship)

Demand Curve slopes downward.

Determinants of Demand (Shift Factors)

Change in Quantity Demanded vs. Change in Demand:

• Change in price = movement along the demand curve

• Change in determinant = shift of the entire demand curve

Supply

Supply = Quantity of a good sellers are willing and able to sell at various prices.

Law of Supply: Price ↑ → Quantity supplied ↑ (direct relationship)

Supply Curve slopes upward.

Determinants of Supply (Shift Factors)

Market Equilibrium

Equilibrium: Where quantity demanded = quantity supplied (no tendency to change).

• Equilibrium price (P*) clears the market

• Equilibrium quantity (Q*) is traded

Disequilibrium Situations

Graph:

Price
  |      Supply
  |        \
  |    P* --X (Equilibrium)
  |        / \
  |      /   \
  |    /     \
  |  Demand   \
  +----------→ Quantity
        Q*

4. Elasticity

Elasticity measures the responsiveness of quantity to a change in another variable.

Price Elasticity of Demand (PED)

Formula:

PED = (% Change in Quantity Demanded) / (% Change in Price)

Always negative (by law of demand), but we often use absolute value.

| |PED| | Type | Meaning | Example |
|——|——|———|———|
| > 1 | Elastic | Qd changes more than price | Luxury goods |
| = 1 | Unit elastic | Qd changes same as price | Proportional |
| < 1 | Inelastic | Qd changes less than price | Necessities (insulin, gasoline) |
| = 0 | Perfectly inelastic | Qd unchanged | Life-saving drug |
| = ∞ | Perfectly elastic | Any price change → Qd zero | Identical commodities |

Determinants of PED

Cross-Price Elasticity of Demand (XED)

Formula: XED = %Δ Qd of Good A / %Δ Price of Good B

Income Elasticity of Demand (YED)

Formula: YED = %Δ Qd / %Δ Income

Price Elasticity of Supply (PES)

Formula: PES = (%Δ Quantity Supplied) / (%Δ Price)

Determinants of PES:

• Time period (longer = more elastic)

• Availability of inputs

• Storage capacity

• Production flexibility

5. Consumer Behavior & Utility

Utility Theory

Utility = Satisfaction or happiness from consuming a good.

Law of Diminishing Marginal Utility: As consumption increases, marginal utility eventually decreases.

Example: Pizza slices

Consumer Equilibrium (Utility Maximization)

Condition: MUx / Px = MUy / Py = … (marginal utility per dollar equal across all goods)

If MUx/Px > MUy/Py → consume more X, less Y.

Indifference Curves & Budget Constraints

Marginal Rate of Substitution (MRS) = Slope of IC = MUx / MUy

6. Production & Costs

Short Run vs. Long Run

Short-Run Cost Concepts

Typical Cost Curves Shape

• MC curve: U-shaped (decreasing then increasing – law of diminishing returns)

• ATC curve: U-shaped (higher at low Q due to AFC; higher at high Q due to MC)

• MC crosses ATC at minimum ATC

Law of Diminishing Marginal Returns

As more of a variable input (labor) is added to a fixed input (capital), marginal product eventually declines.

Long-Run Costs: Economies of Scale

Minimum Efficient Scale (MES): Smallest output level minimizing long-run ATC.

7. Market Structures (Four Types)

Perfect Competition → Monopolistic Competition → Oligopoly → Monopoly
(Increasing market power, decreasing competition)

Comparison Table

Perfect Competition (Benchmark)

• Demand curve for firm: Horizontal (perfectly elastic) at market price P*

• Profit-maximizing rule: MC = MR (and since P = MR, MC = P)

• Short-run: Can earn profits, losses, or break even

• Long-run: Economic profits → entry → price falls → zero economic profit (normal profit only)

• Shut-down rule: Shut down if P < AVC (min)

Monopoly

• Single seller, no close substitutes

• Demand curve for firm: Market demand (downward sloping)

• MR < P (must lower price to sell more)

• Profit-maximizing: MC = MR; then find price from demand curve

• Monopoly markup: P > MC (deadweight loss)

• Barriers to entry: Patents, economies of scale (natural monopoly), ownership of resources, government franchise

Monopolistic Competition

• Many firms, differentiated products

• Downward sloping demand (some pricing power)

• Short-run: Can earn profits

• Long-run: Entry erodes profits → zero economic profit (P = ATC at tangency)

Oligopoly

• Few large firms, strategic interdependence

• Game theory applied (prisoner’s dilemma, Nash equilibrium)

• Collusion: Cooperative behavior (illegal in most countries – cartels)

• Bertrand vs. Cournot vs. Stackelberg models (price vs. quantity competition)

• Kinked demand curve (price rigidity)

8. Market Failures & Government Intervention

Market failure = When free market leads to inefficient allocation.

Externalities

Graphical representation: SMC = PMC + external cost. Optimal Q < market Q for negative externality.

Corrective Measures

9. Key Economic Models & Graphs to Know

10. Important Formulas Summary

11. Glossary of Key Terms

12. Self-Test Questions for Revision

1. Draw a PPF and label efficient, inefficient, and unattainable points.

2. Explain what happens to equilibrium price and quantity if demand decreases AND supply increases simultaneously.

3. Calculate PED: Price rises from $10to$12, quantity demanded falls from 100 to 80. Is demand elastic or inelastic?

4. A firm has FC = $1000,VC=$5 per unit, produces 200 units. Calculate TC, ATC, AFC, AVC.

5. Why does MR < P for a monopolist but MR = P for a perfect competitor?

6. Give one example of a positive consumption externality and one government policy to address it.

7. What is the profit-maximizing condition for any firm?

8. Explain why a price ceiling below equilibrium creates a shortage.

Summary – Key Takeaways

1. Microeconomics studies individual decisions under scarcity.

2. PPF shows trade-offs and opportunity cost.

3. Demand & Supply determine price and quantity in competitive markets.

4. Elasticity measures responsiveness; crucial for pricing and tax policy.

5. Utility theory explains consumer choice (MU per dollar equalization).

6. Cost curves (MC, ATC) guide firm production decisions.

7. Market structures range from perfect competition (efficient) to monopoly (inefficient with deadweight loss).

8. Market failures (externalities, public goods, etc.) justify government intervention.

ECON-2102: PRINCIPLES OF MACROECONOMICS – Complete Study Notes

PART 1: INTRODUCTION TO MACROECONOMICS

1.1 What is Macroeconomics?

Definition: The branch of economics that studies the behavior and performance of an economy as a whole. It focuses on aggregate variables such as total output, employment, inflation, and economic growth.

Macroeconomics vs. Microeconomics:

1.2 Key Macroeconomic Goals

1.3 The Circular Flow Model

Description: Shows the flow of goods, services, and payments between households and firms, with government, financial, and foreign sectors added.

Simplified two-sector model:

• Households: Provide factors of production (labor, capital, land) → receive income (wages, rent, interest, profit) → spend on goods and services

• Firms: Produce goods and services → pay for factors of production → receive revenue from sales

Leakages (withdrawals) vs. Injections:

Equilibrium condition: Leakages = Injections (S + T + M = I + G + X)

PART 2: MEASURING NATIONAL INCOME (GDP)

2.1 Gross Domestic Product (GDP)

Definition: The market value of all final goods and services produced within a country in a given period of time (usually quarterly or annually).

Key features of GDP:

Example (final vs. intermediate): A tire sold to a car manufacturer is an intermediate good (excluded). A tire sold to a consumer for replacement is a final good (included).

2.2 Three Approaches to Measuring GDP (All yield same result)

1. Expenditure Approach (most common):

Formula: GDP = C + I + G + (X – M)

2. Income Approach:

Formula: GDP = National Income + Indirect business taxes + Depreciation + Net foreign factor income

National Income components:

• Compensation of employees (wages, salaries, benefits)

• Proprietor’s income (income of self-employed)

• Rental income

• Corporate profits

• Net interest

3. Value-Added Approach:

Definition: Sum of value added at each stage of production.

Example (value-added for a loaf of bread):

• Farmer grows wheat: sells for $0.50\to valueadded=$0.50

• Miller grinds wheat into flour: sells for $0.80\to valueadded=$0.30

• Baker makes bread: sells for $2.00\to valueadded=$1.20

• Grocer sells bread: sells for $3.00\to valueadded=$1.00

• Total value added = $3.00 = final price

2.3 Nominal vs. Real GDP

Example: An economy produces only apples.

• 2024: Price = $1,Quantity=100\to NominalGDP=$100

• 2025: Price = $1.20,Quantity=110\to NominalGDP=$132, Real GDP (2024 base) = $1\times 110=$110

• Growth in real GDP = ($110-$100)/$100 = 10% (actual output growth)

• Growth in nominal GDP = 32% (includes both output and price increase)

2.4 Price Indices and Inflation

GDP Deflator: (Nominal GDP / Real GDP) × 100

Consumer Price Index (CPI): Measures average price change for a fixed basket of consumer goods and services.

Inflation rate (π): π = (CPI₂ – CPI₁) / CPI₁ × 100%

2.5 Limitations of GDP as a Welfare Measure

Example (GDP paradox): A divorce increases GDP (now two households, more spending) but may reduce overall welfare.

PART 3: UNEMPLOYMENT

3.1 Definitions and Measurement

Labor force: Employed + Unemployed (individuals actively seeking work)

Unemployment rate: (Unemployed / Labor force) × 100%

Labor force participation rate: (Labor force / Working-age population) × 100%

Employment-to-population ratio: (Employed / Working-age population) × 100%

Example: Population = 10,000, Working-age (16+) = 8,000, Employed = 5,000, Unemployed = 500

• Labor force = 5,000 + 500 = 5,500

• Unemployment rate = (500/5,500) × 100% = 9.1%

• Participation rate = (5,500/8,000) × 100% = 68.75%

3.2 Types of Unemployment

3.3 Natural Rate of Unemployment

Definition (NAIRU – Non-Accelerating Inflation Rate of Unemployment): The unemployment rate that exists when the economy is at full employment (no cyclical unemployment).

Natural rate = Frictional + Structural unemployment

Cyclical unemployment = Actual unemployment – Natural rate

• Positive cyclical unemployment → recession (actual > natural)

• Negative cyclical unemployment → expansion (actual < natural — possible but rare)

Causes of changes in natural rate:

• Changes in labor force demographics (more young or old workers)

• Changes in unemployment insurance (more generous benefits may increase frictional unemployment)

• Changes in technology and skills mismatch

• Changes in labor market institutions (union power, minimum wage)

3.4 Costs of Unemployment

Okun’s Law (empirical relationship): For every 1% that unemployment exceeds the natural rate, real GDP is about 2% below potential GDP.

PART 4: INFLATION

4.1 Definition and Measurement

Inflation: Sustained increase in the general price level.

Deflation: Sustained decrease in the general price level (falling prices).

Disinflation: Reduction in the rate of inflation (prices still rising, but more slowly).

4.2 Types and Causes of Inflation

Quantity Theory of Money (Monetarist view): M × V = P × Y

Implication: In long run, if V and Y are stable, inflation is proportional to growth in money supply.

4.3 Effects of Inflation

Example (unexpected inflation – borrower advantage): You borrow $100,000 at 5% fixed interest. Unexpected inflation rises to 10%. You repay with dollars worth less than expected. You win; lender loses.

4.4 Hyperinflation

Definition: Extremely high and accelerating inflation (often >50% per month).

Causes: Seigniorage (government prints money to cover large deficits).

Effects: Collapse of currency value, barter economy, economic breakdown.

Examples: Weimar Germany (1923), Zimbabwe (2000s), Venezuela (2010s).

PART 5: THE AGGREGATE DEMAND – AGGREGATE SUPPLY MODEL

5.1 Aggregate Demand (AD)

Definition: Total quantity of goods and services demanded in the economy at different price levels.

Downward-sloping AD curve (reasons):

AD shift factors (right/left):

5.2 Aggregate Supply (AS)

Short-run Aggregate Supply (SRAS): Upward-sloping. In short run, sticky wages and prices cause output to respond to price level changes.

Long-run Aggregate Supply (LRAS): Vertical at potential GDP (full employment output). In long run, output determined by resources, technology, and institutions, not price level.

SRAS shift factors:

5.3 Macroeconomic Equilibrium

Short-run equilibrium: Intersection of AD and SRAS.

Long-run equilibrium: AD, SRAS, and LRAS all intersect at potential GDP (Y*).

5.4 Recessionary and Inflationary Gaps

Example (recessionary gap – 2008): AD shifted left. Output fell below potential. Unemployment rose. Policy: expansionary (Fed lowered rates; ARRA stimulus spending).

5.5 Shocks and Adjustments

Demand shock (AD shift):

• Positive AD shock → output ↑, price level ↑ (inflationary gap) → in long run, SRAS shifts left (wages rise) → output returns to Y*, price level ↑ further

• Negative AD shock → output ↓, price level ↓ (recessionary gap) → in long run, SRAS shifts right (wages fall) → output returns to Y*, price level ↓

Supply shock (SRAS shift):

• Negative supply shock (oil price rise) → SRAS shifts left → output ↓, price level ↑ (stagflation)

• Policy dilemma: Expanding AD would worsen inflation; contracting AD would worsen recession

PART 6: THE KEYNESIAN PERSPECTIVE AND THE MULTIPLIER

6.1 Keynesian Cross Model

Key insight: In short run, aggregate demand determines output (prices are sticky).

Consumption function: C = C₀ + (MPC × Y_d)

Marginal propensity to save (MPS): MPS = 1 – MPC

6.2 The Multiplier Effect

Definition: An initial change in spending leads to a larger change in total output (income).

Government spending multiplier: ΔY = (1 / (1 – MPC)) × ΔG

Tax multiplier: ΔY = (-MPC / (1 – MPC)) × ΔT

• Tax multiplier is smaller in absolute value than spending multiplier

• Negative sign: tax increase reduces output

Balanced budget multiplier: ΔY = (1) × ΔG (when ΔG = ΔT)

Example (spending multiplier): MPC = 0.8 → Multiplier = 1/(1-0.8) = 5
Government spends $100billion:firstround=$100B; second round (households spend 80% of that) = $80B;thirdround=$64B… total ΔY = $500B.

6.3 Automatic Stabilizers

Definition: Features of fiscal policy that automatically reduce the size of economic fluctuations without additional legislation.

PART 7: FISCAL POLICY

7.1 Definitions and Tools

Fiscal policy: Government use of taxation and spending to influence the economy.

Tools:

7.2 Multipliers (Summary)

7.3 Crowding Out Effect

Definition: Increased government borrowing raises interest rates, reducing private investment (crowds out private spending).

Mechanism:

• G↑ → government borrows more → demand for loanable funds ↑ → interest rate ↑

• Higher interest rate reduces I (investment) and C (durable goods)

Result: Multiplier effect is smaller than 1/(1-MPC) when crowding out occurs.

7.4 Government Debt and Deficits

Debt-to-GDP ratio: Debt / GDP (more meaningful measure than absolute debt)

Concerns about high debt:

• Interest payments consume tax revenue

• Potential for higher future taxes

• Risk of crowding out

• Default risk (for countries borrowing in foreign currency)

When high debt is less concerning:

• Debt owned domestically (owed to own citizens)

• Borrowing to finance productive investment (public infrastructure, education)

• Demographics favorable (young population)

PART 8: MONEY, BANKING, AND MONETARY POLICY

8.1 Definitions of Money

Functions of money:

Measures of money supply:

8.2 How Banks Create Money (Fractional Reserve Banking)

Key concept: Banks only need to keep a fraction of deposits as reserves; can lend the rest.

Reserve ratio (rr): Fraction of deposits held as reserves. R = rr × D

Money multiplier: 1 / rr

Example: rr = 10% (0.10). Money multiplier = 1/0.10 = 10.
Bank receives $100 deposit:

• Must keep $10 in reserve

• Can lend $90 (creates new money when borrower spends it)

• Borrower spends $90;merchantdeposits$90 → bank keeps $9reserve,lends$81…

• Total money created: $100\times 10=$1,000 (including original deposit)

8.3 Central Bank (Federal Reserve in US)

Functions:

• Conduct monetary policy

• Lender of last resort (prevents bank runs)

• Regulate banks

• Manage payment system

Monetary Policy Tools:

8.4 Monetary Policy Transmission Mechanism

Contractionary policy example:

1. Central bank sells bonds (OMO) → money supply decreases

2. Interest rates rise (less money available)

3. Higher interest rates reduce investment and consumption of durable goods

4. Aggregate demand decreases

5. Output falls and/or price level rises less

Expansionary policy example (reverse):

1. Central bank buys bonds → money supply increases

2. Interest rates fall

3. Investment and consumption increase

4. Aggregate demand increases

5. Output rises and/or price level rises more

8.5 Monetary Policy and Long-Run Neutrality

Classical dichotomy and monetary neutrality:

• In the long run, changes in money supply affect only nominal variables (prices, wages, exchange rates)

• In the long run, changes in money supply do NOT affect real variables (output, employment, real interest rate)

Short-run non-neutrality: Due to sticky wages and prices, monetary policy can affect real output temporarily.

PART 9: PHILLIPS CURVE

9.1 Short-Run Phillips Curve

Definition: Inverse relationship between unemployment and inflation (in short run).

Mechanism: Expansionary policy reduces unemployment but increases inflation; contractionary policy reduces inflation but increases unemployment.

Example (1960s): As unemployment fell, inflation rose (observations consistent with SRPC).

9.2 Long-Run Phillips Curve

Definition: Vertical at the natural rate of unemployment (NAIRU). No long-run trade-off between unemployment and inflation.

Reason: In long run, expectations adjust. Expansionary policy leads only to higher inflation, not lower unemployment.

Natural rate hypothesis: Unemployment eventually returns to natural rate regardless of inflation.

9.3 Expectations-Augmented Phillips Curve

Formula: π = πᵉ – β(u – uₙ) + ε

Key insight: When unemployment is below natural rate (u < uₙ), actual inflation > expected inflation. Over time, expectations adjust upward, shifting SRPC up.

9.4 Disinflation and the Sacrifice Ratio

Sacrifice ratio: Percentage of GDP lost for each 1% reduction in inflation.

Example: Sacrifice ratio = 5. To reduce inflation from 6% to 2% (4% reduction), output falls by 5 × 4 = 20% of annual GDP.

Rational expectations critique (Lucas): If policy change is credible, disinflation can occur with little or no output loss (expectations adjust immediately).

Example (Volcker disinflation, 1979-82): Fed raised rates sharply to break inflation. Recession followed (sacrifice ratio observed). But inflation fell permanently.

PART 10: ECONOMIC GROWTH

10.1 Measuring Growth

Economic growth: Increase in real GDP per capita over time.

Rule of 70: Number of years to double = 70 / annual growth rate (%)

Example: 2% annual growth → doubling time = 70/2 = 35 years.
7% annual growth → doubling time = 10 years.

10.2 Production Function and Growth Accounting

Aggregate production function: Y = A × F(K, L, H, N)

Growth accounting: %ΔY = %ΔA + α%ΔK + β%ΔL + γ%ΔH (with α+β+γ=1)

Key lesson: Sustained growth comes primarily from technological progress (ΔA), not just capital accumulation (diminishing returns).

10.3 Determinants of Productivity

10.4 Convergence Hypothesis

Definition: Poor countries tend to grow faster than rich countries (catch up), assuming similar institutions and policies.

Conditional convergence: After controlling for differences in savings rates, education, institutions, etc., poorer countries do grow faster.

Why not all countries converge?

• Poor institutions (corruption, weak property rights)

• Poor policies (trade barriers, price controls)

• Geography (landlocked, tropical diseases)

• Conflict and political instability

PART 11: INTERNATIONAL FINANCE

11.1 Balance of Payments

Definition: Record of all economic transactions between residents of a country and the rest of the world.

Identity: Current account + Capital account + Financial account = 0 (balance of payments always balances).

11.2 Exchange Rates

Nominal exchange rate (e): Price of one currency in terms of another.

Real exchange rate (ε): ε = e × (P_domestic / P_foreign)

Appreciation vs. Depreciation:

Determinants of exchange rates (long run):

• Relative price levels (higher inflation → depreciation)

• Relative interest rates (higher rates → appreciation)

• Trade barriers (tariffs, quotas → appreciation)

• Productivity (higher productivity → appreciation)

PART 12: MACROECONOMIC POLICY DEBATES

12.1 Active vs. Passive Policy

12.2 Rules vs. Discretion

Problems with discretion:

• Time inconsistency (promise low inflation; then surprise expansion)

• Political business cycles (pre-election expansion)

Solution: Independent central bank with clear mandate (e.g., Federal Reserve, ECB)

12.3 Should Tax Cuts Target Demand or Supply?

QUICK REFERENCE TABLES

Key Macroeconomic Formulas

Policy Response Matrix

Business Cycle Indicators

SAMPLE EXAM QUESTIONS

Question 1 (GDP Calculation)

Using the following data (billions of dollars), calculate GDP: Consumption = 8,000; Investment = 2,500; Government spending = 2,200; Exports = 1,800; Imports = 2,000; Depreciation = 1,200; Indirect business taxes = 800.

Model Answer:

• Use expenditure approach: GDP = C + I + G + (X – M)

• GDP = 8,000 + 2,500 + 2,200 + (1,800 – 2,000) = 8,000 + 2,500 + 2,200 – 200 = $12,500 billion

• (Depreciation and indirect taxes are not used in expenditure approach; they are used in converting GDP to NDP or NI)

Question 2 (Unemployment)

A country has a working-age population of 200 million. 120 million are employed, 8 million are unemployed. Calculate: (a) labor force; (b) unemployment rate; (c) labor force participation rate.

Model Answer:

• (a) Labor force = Employed + Unemployed = 120M + 8M = 128 million

• (b) Unemployment rate = (8M / 128M) × 100% = 6.25%

• (c) Participation rate = (128M / 200M) × 100% = 64%

Question 3 (Multiplier)

If the marginal propensity to consume (MPC) is 0.75, calculate: (a) the government spending multiplier; (b) the tax multiplier; (c) the effect on GDP of a $100billionincreaseingovernmentspending;(d)theeffectonGDPofa$100 billion decrease in taxes.

Model Answer:

• (a) Spending multiplier = 1/(1 – MPC) = 1/(0.25) = 4

• (b) Tax multiplier = -MPC/(1 – MPC) = -0.75/0.25 = -3

• (c) ΔY = multiplier × ΔG = 4 × $100B=\ast \ast$400 billion increase**

• (d) ΔY = tax multiplier × ΔT = (-3) × (-$100B)=\ast \ast$300 billion increase** (Note: tax cut is negative ΔT)

Question 4 (Inflation and Money Supply)

Using the quantity equation of money, if the money supply grows by 6%, real GDP grows by 2%, and velocity is constant, what is the inflation rate?

Model Answer:

• Quantity equation: M × V = P × Y

• Growth form: %ΔM + %ΔV = %ΔP + %ΔY

• Given: %ΔM = 6%, %ΔV = 0 (constant), %ΔY = 2%

• 6% + 0 = %ΔP + 2%

• %ΔP = 6% – 2% = 4% inflation

Let me know if you would like:

• A printable formula sheet for exam revision

• Additional practice problems with answer keys

• Country case studies (US, Japan, China, Eurozone)

• Notes on specific monetary policy episodes (Volcker, Bernanke, post-2008)

ECON-2204: Introduction to Statistical Methods in Economics – Complete Study Notes

Course Overview

Statistical Methods in Economics applies statistical techniques to economic data to analyze relationships, test hypotheses, and make predictions. This course bridges economic theory and real-world data, providing tools for empirical analysis in fields such as labor economics, finance, econometrics, and public policy .

Core Question: How do we use data to infer economic relationships and test economic theories?

Prerequisites: Basic calculus, introductory economics, and high school algebra .

PART 1: FOUNDATIONS OF STATISTICS FOR ECONOMICS

1.1 Why Statistics in Economics?

1.2 Types of Economic Data

1.3 Variables in Economic Analysis

PART 2: DESCRIPTIVE STATISTICS

2.1 Measures of Central Tendency

Economic Insight: For income data, median is often preferred over mean because the mean is pulled upward by very high incomes (skewed distribution). The median better represents “typical” household income.

2.2 Measures of Dispersion (Variability)

Coefficient of Variation (CV): CV = σ/μ × 100% – Allows comparison of variability across different units or scales (e.g., comparing wage dispersion across countries with different average wages).

2.3 Shape of Distribution

Skewness Interpretation:

• 0 = Symmetric (normal distribution)

• Positive = Right-skewed (tail on right) – most income data

• Negative = Left-skewed (tail on left) – exam scores (few very low)

2.4 Data Visualization for Economics

PART 3: PROBABILITY FOR ECONOMICS

3.1 Basic Probability Concepts

Axioms of Probability:

1. P(S) = 1 (something must happen)

2. For mutually exclusive events: P(A ∪ B) = P(A) + P(B)

3.2 Random Variables

3.3 Probability Distributions for Economics

Discrete Distributions:

Continuous Distributions:

Standard Normal (Z) Transformation: Z = (X - μ)/σ – allows probability calculations for any normal variable.

3.4 Expected Value and Variance

Properties of Expectation:

• E[aX + b] = a·E[X] + b

• Var(aX + b) = a²·Var(X)

• For independent X,Y: E[XY] = E[X]E[Y]

3.5 Covariance and Correlation

Correlation does NOT imply causation (critical economic insight). Ice cream sales and drowning are correlated (summer), but neither causes the other – confounded by temperature.

PART 4: SAMPLING AND ESTIMATION

4.1 Sampling Concepts

Why sample? Cost, time, and sometimes impossibility (populations are infinite, or destructive testing would consume the product – but in economics, you can ask all 1000 households, but surveying all 100 million is too costly).

4.2 Sampling Methods

4.3 Sampling Distribution

Definition: The distribution of a statistic (e.g., sample mean) over all possible samples of a given size from the population.

The Central Limit Theorem (CLT) – The most important theorem in statistics for economics:

For any population with mean μ and variance σ², the sampling distribution of the sample mean (x̄) approaches a normal distribution as sample size n increases, regardless of the shape of the population distribution.

Implications:

• E[x̄] = μ (unbiased)

• Var(x̄) = σ²/n

• Standard Error (SE) = σ/√n

Economic Application: We can make probabilistic statements about how close x̄ is to μ, even if the population distribution is not normal (e.g., income). For large n (typically n≥30, but for highly skewed distributions you may need more), the sample mean is approximately normal, allowing confidence intervals and hypothesis tests based on the normal distribution.

4.4 Estimation

Confidence Interval for μ (σ known, or large n – approximate using sample standard deviation s):