Unit 1: Demand analysis & managerial decision-making
Managerial Economics notes · PTU syllabus (BCOMGE 101-18)
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Unit summary
Managers constantly choose — what to produce, how much, at what price. Managerial economics applies economic tools to these choices. This unit covers opportunity cost, the production possibility curve, the demand function and its determinants, elasticity of demand and demand forecasting.
After this unit you can
- Explain the nature and scope of managerial economics and the opportunity cost principle
- Draw and interpret a production possibility curve
- Explain the demand function, law of demand and its exceptions
- Measure price, income and cross elasticity of demand and explain forecasting methods
PTU syllabus topics
- Opportunity cost
- production possibility curve
- demand function
- demand elasticity
- demand forecasting
Price elasticity
Ep = % change in quantity / % change in price
Income elasticity
Ey = % change in quantity / % change in income
Cross elasticity
Exy = % change in qty of X / % change in price of Y
Rule of thumb
Ep > 1 elastic, < 1 inelastic
Luxuries tend to be elastic
Topic 1
Managerial economics and decision-making
Managerial economics is the integration of economic theory with business practice for the purpose of facilitating decision-making and forward planning by management (Spencer and Siegelman).
- Nature: micro-economic in character, pragmatic, normative (prescriptive), uses macro-economics for environment, management-oriented.
- Scope: demand analysis and forecasting, production and cost analysis, pricing decisions, profit management, capital budgeting, market structure analysis.
Opportunity cost
Value of the next best alternative forgone
Incremental principle
Compare incremental revenue with incremental cost
Marginal principle
Produce where MR = MC
Time perspective
Short-run and long-run effects
Discounting
Future values discounted to present
Equi-marginal principle
Allocate resources so that marginal returns are equal everywhere
Example
A graduate who joins a family business instead of a ₹6 lakh-a-year job bears an opportunity cost of ₹6 lakh a year — it must be counted as an economic cost even though no cash is paid.
Topic 2
Production possibility curve
A production possibility curve (PPC) shows the maximum combinations of two goods an economy (or firm) can produce with given resources and technology, when resources are fully and efficiently used.
| Combination | Wheat (tonnes) | Cloth (units) | Opportunity cost of 1 extra unit of cloth |
|---|---|---|---|
| A | 15 | 0 | — |
| B | 14 | 1 | 1 tonne wheat |
| C | 12 | 2 | 2 tonnes |
| D | 9 | 3 | 3 tonnes |
| E | 5 | 4 | 4 tonnes |
| F | 0 | 5 | 5 tonnes |
- The PPC is concave to the origin because of increasing marginal opportunity cost — resources are not equally suited to both goods.
- A point inside the curve shows unemployment or inefficiency; a point outside is unattainable.
- The PPC shifts outward with more resources or better technology (economic growth).
Exam tip
The PPC illustrates the three central problems of an economy — what, how and for whom to produce.
Topic 3
Demand function and law of demand
Demand is the quantity of a commodity that consumers are willing and able to buy at a given price during a period. Demand function: Qd = f(P, Pr, Y, T, A, E, N) — own price, prices of related goods, income, tastes, advertisement, expectations, population.
- Law of demand: other things being equal, quantity demanded rises when price falls and falls when price rises.
- Reasons: income effect, substitution effect, law of diminishing marginal utility, new buyers, multiple uses.
- Exceptions: Giffen goods, Veblen (prestige) goods, expectation of further price rise, ignorance, necessities.
Cause
Change in own price
Change in other determinants
Terms
Extension and contraction
Increase and decrease
Graph
Same curve
New curve to the right or left
Topic 4
Elasticity of demand
Elasticity of demand measures the responsiveness of quantity demanded to a change in a determinant.
Price elasticity (Ep)
% change in quantity demanded ÷ % change in price
Arc elasticity
(ΔQ ÷ ΔP) × ((P1 + P2) ÷ (Q1 + Q2))
Income elasticity (Ey)
% change in quantity ÷ % change in income
Cross elasticity (Exy)
% change in quantity of X ÷ % change in price of Y
Total outlay method
Ep > 1 if total spending rises when price falls
| Degree of price elasticity | Value | Example |
|---|---|---|
| Perfectly elastic | ∞ | Theoretical; perfect competition firm's demand |
| Relatively elastic | > 1 | Luxuries, cars, air travel |
| Unitary elastic | = 1 | Rectangular hyperbola |
| Relatively inelastic | < 1 | Necessities — salt, medicines |
| Perfectly inelastic | 0 | Life-saving drugs (approx.) |
Example
Price falls from ₹10 to ₹8 and quantity rises from 100 to 130 units. Ep = (30/100) ÷ (2/10) = 0.30 ÷ 0.20 = 1.5 — elastic, so cutting price raises total revenue (₹1,000 → ₹1,040).
- Income elasticity: positive for normal goods (> 1 luxury, 0–1 necessity), negative for inferior goods.
- Cross elasticity: positive for substitutes (tea and coffee), negative for complements (car and petrol).
- Determinants of price elasticity: availability of substitutes, nature of the good, proportion of income spent, number of uses, time period, habits.
- Managerial uses: pricing, taxation policy, wage fixing, joint products, international trade.
Topic 5
Demand forecasting
Demand forecasting is estimating future demand for a product under given conditions.
Survey methods
Consumer survey (census or sample), opinion poll — expert opinion, Delphi, sales-force composite
Statistical methods
Trend projection (least squares), moving averages, barometric (leading indicators), regression and econometric models
Other
Test marketing, controlled experiments
- Steps: set objectives, choose time period (short or long term), identify determinants, choose method, collect data, estimate and interpret.
- Criteria of a good method: accuracy, simplicity, economy, availability of data, flexibility, durability.
Example
Using least squares on five years' sales (Y = a + bX with X coded −2 to +2): if ΣY = 500 and ΣXY = 60, ΣX² = 10, then a = 100, b = 6; forecast for year 6 (X = 3) = 100 + 6 × 3 = 118.
Key terms
- Opportunity cost
- Value of the next best alternative forgone
- Production possibility curve
- Combinations of two goods producible with given resources
- Demand function
- Relationship between quantity demanded and its determinants
- Price elasticity of demand
- Responsiveness of quantity demanded to price change
- Demand forecasting
- Estimating future demand
Quick revision
- Concepts: opportunity cost, incremental, marginal, discounting, equi-marginal.
- PPC concave due to increasing opportunity cost.
- Law of demand and its exceptions (Giffen, Veblen).
- Ep > 1 elastic; cross elasticity + substitutes, − complements.
- Forecasting: survey and statistical methods.
Important exam questions
Practice questions written to the PTU exam pattern for this unit's syllabus: short answers (Section A style) and long answers (Sections B and C style).
Short-answer questions
- Q1.Define managerial economics.
- Q2.What is opportunity cost?
- Q3.Why is the PPC concave to the origin?
- Q4.Distinguish change in demand and change in quantity demanded.
- Q5.What is cross elasticity of demand?
- Q6.What is the Delphi method?
Long-answer questions
- Q1.Explain the nature, scope and fundamental concepts of managerial economics.
- Q2.Explain the production possibility curve and its uses.
- Q3.Explain the concept, types, measurement and determinants of elasticity of demand.
- Q4.Discuss the methods of demand forecasting.
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