Unit 1: Fundamentals of Microeconomics — ECO 203 Microeconomics for Business Study Notes

Difficulty: ★★★ | High-yield focus: Memorize microeconomics definition, scarcity, opportunity cost, and positive vs normative economics. Key exam mastery: Evaluate microeconomic market models and production possibility frontiers in transition economies.

Part 1: Core Concepts (2 Marks)

Academic Definition of Microeconomics

According to Paul A. Samuelson and William D. Nordhaus (★), “Microeconomics is the branch of economics which is concerned with the behavior of individual entities such as markets, firms, and households.”

Similarly, N. Gregory Mankiw defines microeconomics as “the study of how households and firms make decisions and how they interact in specific markets.”

Core Characteristics of Microeconomics

Individualistic Focus: Disaggregates the macro-economy to analyze the economic choices of single consumers, specific firms, or isolated commodity markets.
Price Theory Foundation: Focuses centrally on the price mechanism as the primary allocator of scarce societal resources.
Ceteris Paribus Assumption: Operates on the analytical principle of “other things being held equal” to isolate single cause-and-effect relationships.
Normative vs. Positive Dichotomy: Distinguishes between positive economics (factual statements of “what is”) and normative economics (value judgments of “what ought to be”).

Concept of Opportunity Cost

Opportunity cost is the value of the next best alternative forgone when a choice is made. Mathematically:

\text{Opportunity Cost} = \text{Return on Best Forgone Option} - \text{Return on Chosen Option}

Part 2: Structural Frameworks (10 Marks)

1. Mankiw’s Ten Principles of Economics (Framework Breakdown)

MANKIW’S TEN ECONOMIC PRINCIPLES

HOW PEOPLE MAKE	HOW PEOPLE INTERACT	HOW THE ECONOMY
DECISIONS (1-4)	(5-7)	WORKS AS A WHOLE
1. People face trade-offs	5. Trade can make	8. Standard of
2. Cost is what you give	everyone better off	living depends
up to get it	6. Markets are usually a	on production
3. Rational people think	good way to organize	9. Prices rise
at the margin	economic activity	when govt
4. People respond to	7. Governments can	prints money
incentives	sometimes improve market outcomes	10. Short-run inflation-unemp trade-off

Category A: How People Make Decisions

Principle 1: People Face Trade-offs: To obtain one commodity, we must relinquish another (e.g., “guns vs. butter” at national level; leisure vs. labor at individual level).
Principle 2: Cost is What You Give Up: Rational decision-making requires comparing full opportunity costs, not merely direct financial outlays.
Principle 3: Rational People Think at the Margin: A rational decision-maker takes an action if and only if the Marginal Benefit ( $MB$ ) exceeds Marginal Cost ( $MC$ ): $MB \ge MC$ .
Principle 4: People Respond to Incentives: Behavioral adjustments occur when marginal benefits or marginal costs shift.

2. The Production Possibility Frontier (PPF)

Production Possibility Frontier (PPF) & Opportunity Cost

\text{MRT}_{xy} = -\frac{\Delta Y}{\Delta X} = \frac{MC_x}{MC_y}

Economic State / Output Region	Curve Trajectory & Relationships	Analytical & Decision Rule
Points on the Frontier (A, B)	Full and efficient employment of all national resources	Productive efficiency; moving along curve requires opportunity sacrifice
Interior Point (C)	Underemployment of labor or capital resources	Inefficient; production can expand without sacrifice
Exterior Point (D)	Beyond current resource endowment and technology	Unattainable in short run; requires economic growth or tech breakthrough

Points on the Curve (A, B): Attainable and Pareto-efficient (full employment of inputs).
Points Inside the Curve (C): Attainable but economically inefficient (idle capital or unemployment).
Points Outside the Curve (D): Unattainable given current technology and resource endowments; reachable only via economic growth, capital deepening, or technological advancement.
Slope of the PPF: Represents the Marginal Rate of Transformation (MRT):
$MRT_{xy} = -\frac{\Delta Y}{\Delta X} = \frac{MC_x}{MC_y}$

Part 3: Distinction Tables

Comparison: Microeconomics vs. Macroeconomics

Basis of Comparison	Microeconomics	Macroeconomics
Unit of Analysis	Individual economic agents (a consumer, a household, a firm, an industry).	The aggregate national or global economy as an integrated whole.
Core Central Theory	Price Theory (Determination of relative prices of goods and inputs).	Income & Employment Theory (National income, aggregate output, inflation).
Major Variables	Individual demand, supply, elasticity, firm production costs, factor pricing.	GDP, GNP, national employment, aggregate price index (CPI), balance of payments.
Underlying Assumptions	Assumes macro aggregates (national income, overall price level) are constant.	Assumes individual relative distribution of income and prices is constant.

Comparison: Positive Economics vs. Normative Economics

Dimension	Positive Economics	Normative Economics
Core Meaning	Objective and scientific analysis explaining “what is, was, or will be”.	Subjective value judgments indicating “what ought to be or should be”.
Verification	Empirically testable and verifiable against observed market data.	Cannot be tested or refuted using empirical data; reflects moral or ethical values.
Nature of Statements	Descriptive, causal, and analytical facts.	Prescriptive recommendations and policy directives.
Example	“Imposing a 13% VAT on mobile phones increases their retail price.”	“The government ought to exempt essential medicines from all VAT to protect the poor.”

Part 4: Worked Problems & Exam Traps

Numerical Archetype: Marginal Thinking & Optimal Decision Rule

Problem: A commercial passenger airline operates a 120-seat flight between Kathmandu and Biratnagar. The total cost of flying the aircraft is NPR 360,000, yielding an average cost per seat of NPR 3,000. Moments before departure, an unreserved seat remains vacant. A stand-by student passenger offers NPR 1,800 for the seat. Should the airline accept the student’s offer?

Solution Workflow:

Given Parameters:
- Total Fixed Flight Cost ( $TC$ ) = NPR 360,000
- Total Capacity = 120 seats
- Average Cost ( $AC$ ) = $\frac{360,000}{120} = \text{NPR } 3,000$
- Offered Ticket Price ( $MB$ ) = NPR 1,800
- Additional cost of carrying one stand-by passenger (in-flight drink, minor fuel increment) = $MC = \text{NPR } 300$
Decision Rule:
$\text{Accept if } MB > MC$

$\text{Marginal Benefit (Revenue)} = \text{NPR } 1,800$

$\text{Marginal Cost} = \text{NPR } 300$

$\text{Net Marginal Gain} = 1,800 - 300 = \text{NPR } 1,500$
Conclusion Statement: The airline must accept the stand-by passenger at NPR 1,800. Although the price is below the average cost of NPR 3,000, it substantially exceeds the marginal cost of NPR 300, contributing an additional NPR 1,500 toward offsetting fixed overhead.

Common Board Exam Trap: Students erroneously reject this offer by arguing that “NPR 1,800 is less than the average cost of NPR 3,000, causing a loss of NPR 1,200”. In economics, sunk fixed costs are irrelevant to short-run marginal decisions. Only marginal cost and marginal benefit determine rationality.

Students lose marks here because they confuse microeconomic resource allocation with macroeconomic aggregate stabilization policies.

Microeconomics for Business

Chapter notes

Unit 1: Fundamentals of Microeconomics· 5 LHs· ~6 marks