CAVENDISH COLLEGE LESSON NOTE FOR FIRST TERM ECONOMICS SSS2 UPDATED..docx

CAVENDISH COLLEGE LESSON NOTE FOR FIST TERM YEAR 11
Subject Economics
Week 1
Class Ss2
Topic MEASURES OF CENTRAL TENDENCY
WEEK ONE
MEASURES OF CENTRAL TENDENCY
CONTENT
 MEAN
 MODE
 MEDIAN
MEASURES OF CENTRAL TENDENCY: measures of central tendency also called measures
of location, is the statistical information that gives the middle or centre or average of a set of
data. Measures of central tendency include arithmetic mean, median and mode.
MEAN: This is the average of variables obtained in a study. It is the most common kind of
average. For group data the formula for calculating the mean is ∑fx.
∑f
Where, Ʃ = Represent a Greek later denoting “Sum of”
F=frequency
X=observation
MEDIAN: It is the middle number in any given distribution. The formula is
Median = L + (N2-Fb)c
f
Where; L = Lower class limit.

N = Summation 0f the frequency.
Fb = Cumulative frequency before the median class.
f = frequency of the median class.
c= Class size.
MODE: It is the number that appears most in any given distribution, i.e the number with the
greatest frequency. When a series has more than one mode, say two, it is said to be bi-modal or
tri-modal for three.
Mode= L + D1
D1+D2
Where, M=mode
L=the lower class boundary of the modal class.
D1=the frequency of the modal class minus the frequency of the class before the modal
class.
D2=the frequency of the modal class minus the frequency of the class after it.
C=the width of the modal class.
Example: The table below shows the marks of students of JSS 3 mathematics.
Use the information above to calculate the following:
A. the mean
B. the median
C. the mode
Marks
1-5 6-10 11-15 16-20 21-25 26-30
Frequency 2 3 4 5 6 7

Solution
Mark frequency mid-point fx
1-5 2 3 6
6-10 3 8 24
11-15 4 13 52
16-20 5 18 90
21-25 6 23 138
26-30 7 28 196
27 506
A. Mean= ∑fx = 50627
Ʃf =18.7
B. median
Mark F Cf
1-5 2 2
6-10 3 5
11-15 4 9
16-20 5 14
21-25 6 20
26-30 7 27
L1= 15.5
N2 =272=13.5
Fb =9
F =5
C= 5
M=15.5+ (13.5-9)5
5
M=20
C. mode= L+ D1
D1+D2
L1=20.5

D1=7-6=1
D2=7-0=7
C=5
M=25.5+ (11+7)5
M=26.125.
EVALUATION
The table below shows the weekly profit in naira from a mini-market.
You are required to calculate:
A. The mean.
B. The median.
C. The mode.
Weekly
profit(#)
1-10 11-20 21-30 31-40 41-50 51-60
Frequency 6 6 12 11 10 5
READING ASSIGNMENT
1. Essential Economics 16-19
GENERAL EVALUATION QUESTIONS
1. Outline the merits of a Joint Stock Company.
2. Describe the problems facing Agriculture in Nigeria.
3. Outline the main features of Malthusian theory of Population.
4. What is money?
5. List five characteristics of money.
WEEKEND ASSIGNMENT
1. Which of the following is not a set of measure of central tendency? (a) mode and mean
(b) mean and median (c) mean and percentile (d) mode and median
2. The most frequently occurring value in a give data is (a) mean ( b ) mode (c ) range (d)
median.

3. The formula (n+1)th is for calculating (a ) median (b ) mode (c ) mean (d) range.
2
4. The L1 in the formula for the calculation of measures of location represents......... (a)
lower class boundary of the median class (b) actual frequency of the modal class (c)
upper class boundary of the median class (d) frequency of the class just after the median
class
5. The formation of cumulative frequency is necessary for the calculation of............ (a)
mean (b) range (c) median (d) mode
SECTION B
The following table shows the distribution of marks scored by a class of students in a promotion
examination.
Marks Number of students
10-29 6
30-39 5
40-49 7
50-59 10
60-69 5
70-79 4
80-89 3
1. Calculate the mean mark.
2. Find the mode.

Subject Economics
Week 2
Class Ss2
Topic measures dispersion of group frequency distribution
WEEK TWO
MEASURES OF DISPERSION OF A GROUPED FREQUENCY DISTRIBUTION
CONTENT
 Range
 Mean Deviation
 Variance
 Standard Deviation
MEASURES OF DISPERSION: also known as measures of variability, refers to the
degree of spread of numerical value in a distribution. These measures are the range, mean
– deviation, standard deviation, variance, coefficient of variation, etc.
The Range: The range of a data is the difference between the highest and the lowest
value in the data. The formula for calculation of range is:
Range = Highest value – Lowest value
The Mean Deviation: This is defined as the arithmetic Mean of all absolute Deviation
from the mean. = ∑f/x- x/
∑f
Variance: The variance refer to the arithmetic mean of the squares of the deviation of the
observation from the true mean. It is also referred to as the :mean square deviation”

Variance = ∑f(X – X)2
∑f
Standard Deviation: This is the square root of the variance. It is also referred to as the
“root mean square deviation”.
Standard Deviation =
∑f(X – X )2
Ʃf
Example:
The data below shows the weight of 50 students to the nearest kg.
65, 58, 51, 36, 23 40 53 59 70 51 46 59 50 67 46 39 61 62 73 60 71 51 47 32 48 40 40 51
58 67 60 69 43 52 37 26 38 50 59 40 44 54 42 68 74 45 39 48 55.
a. Prepare a grouped frequency table
b. Calculate:
i. The range
ii. The mean deviation
iii. The variance
iv. The standard deviation
NB: Note that the standard Deviation is the positive square root of the variance.
∑fx = 2535 = 50.7
∑f 50
Class F Mid-
point
X
FX
_
/X- X/
_
F/X-X/
_
(X-X )2
_
F(X-X)2
21-30 2 25.5 51 25.5 50.4 650.25 1300.5
31-40 10 35.5 355 15.2 152 231.04 2310.40
41-40 12 45.5 546 5.2 62.4 27.04 324.48
51-60 15 55.5 832.
5
4.8 72 23.04 345.60
61-70 8 65.5 524 14.8 118.4 219.04 1752.32
71-80 3 75.5 226.
5
24.8 74.4 615.04 1845.12
50 2535 529.60 7878.42

(i) Range = Highest score –Lowest score
= 74 - 23
= 51kg
(ii) Mean Deviation
=∑f/ X –X/ = 529.60 = 10.59kg
∑f 50
(iii) Variance = ∑f/X – X /2
∑f
= 7878.42 = 157.6kg
50
(iv) Standard Deviation
∑f/X – X /2
157.6
∑f = =12.55kg
EVALUATION QUESTION
1) How is the mid-point (X) ascertained in a grouped frequency table?
2) State two advantages of the mean over other measures of central tendency (i.e
median and mode)
3) The table below shows the income of forty Workers in a factory in N
61 78 70 83 92 67 66 83
76 68 79 84 82 86 81 60
78 77 86 77 81 92 80 70
70 40 75 60 74 82 77 87
63 94 76 87 81 77 87 84.
Using a class interval of 40-49, 50-59 etc
A. Construct a grouped frequency table of the distribution.
B. Calculate the mean of the distribution.
READING ASSIGNMENT

Read the advantages and disadvantages of the range, mean deviation and standard
deviation.
1. Give five reasons why government participates in business enterprises.
2. Define ageing population.
3. Explain the sources of finance available to a public limited liability business.
4. Explain any three weapons that can be used by a trade union during trade
dispute.
5. What is occupational mobility?
WEEKEND ASSIGNMET
1. In a class of 5 students the following scores were obtained in a mathematics test
10,2,6,7,12. What is the median score (A) 2 (B) 4(C) 6 (D) 7
2. Which measure of central tendency can be applied to find the highest goal scorer
in a football match (A) mean (b) Mode (C) Median (D) range
3. If the following scores 2, 4, 6, and 10 with frequencies 3,5,7, and 10 respectively
makes up a distribution, then the mean score is (A) 5.7 (B) 6.7 (C) 7.5 (D) 5.4
4. In the formula X = ∑fx
∑f
∑fX stands for (A) total number of observations (B) Sum of frequencies times
observations (C) Sum of frequencies (D) number of elements times frequencies
5. The most reliable measure of central tendency is (a) Mode (b) median (c)
Histogram (d) mean
SECTION B
1. Give the definition of the mean deviation and the standard deviation
2. Explain the difference between continuous data and discrete data.

CAVENDISH COLLEGE LESSON NOTE FOR FIST TERM
Subject Economics
Week 3
Class Ss2
Topic THEORY OF CONSUMER BEHAVIOR
WEEK THREE
THEORY OF CONSUMER BEHAVIOUR
CONTENT
 Definition of Utility
 Cardinal school of thought/Assumption
 Concept of Total, Average and Marginal Utility
 The law of Diminishing Marginal Utility.
THEORY OF CONSUMER BEHAVIOUR
The theory of consumer behaviour is also known as the theory of household behaviour. It
is primarily concerned with how the consumer or household tries to satisfy his/her wants
by dividing his/her limited amount of income between the various commodities that give
him equal amount of satisfaction.

WHAT IS UTILITY? Utility can be defined as the satisfaction derived from the
consumption of a given commodity. Utility therefore, is relative to a consumer,
depending on the time, place, form, etc.
EVALUATION
1. Define utility.
2. What is consumer behavior?
TYPES OF UTILITY
1. Form Utility: form utility refers to the change in the form or structure of a commodity
during its manufacturing process in order to increase its utility.
2. Place Utility: place utility involves the changing of location from one geographical area
where it has little utility to another area where its utility is higher.
3. Time utility: This refers to the satisfaction a consumer will derive from the consumption
of a particular commodity at a given time.
CONCEPT OF TOTAL, AVERAGE AND MARGINAL UTILITY
TOTAL UTILITY: This is the total amount of satisfaction a consumer derives from the
consumption of a particular commodity at a point in time.
y
Units of
Utility
TU
X
Total utility curve
1 2 3 4 5
40
30
20
10

AVERAGE UTILITY: This derived by dividing total utility by the units of the
commodity consumed. IT is also the satisfaction which a consumer derives per unit of a
commodity consumed. AU = TU
Quantity consumed
Y
Utility
AU
0 X
Unit of commodity consumed
MARGINAL UTILITY: This means the additional satisfaction a consumer derives from
the consumption of additional unit of a particular commodity. It is then the change in the
total utility as a result of the consumption of additional unit of a commodity. MU =
∆TU/∆Q
y
Utility
X
Units of commodity consumed

UTILITY SCHEDULE
Quantity of Goods
consumed
Total Utility Average Utility Marginal Utility
1 4 4 -
2 7 3.5 3
3 9 3 2
4 10 2.5 1
5 10 2.0 0
RELATIONSHIP BETWEEN TOTAL UTILITY AND MARGINAL UTILITY
1. The MU begins to fall right after the first unit of the commodity has been
consumed and continues to diminish until it reaches zero level on x – axis and
below.
2. At the point where the MU reaches zero level on the x – axis, TU reaches its
maximum point.
3. When the MU cuts the x – axis, TU begins to fall from its peak.
4. When the MU descends below the x – axis and becomes negative, the TU curve
begins to slope downward
TOTAL AND MARGINAL UTILITY CURVES
Utility Y
TU
X
MU
Relationship between TU and MU

EVALUATION
1 Calculate the missing value from the table below.
Quantity of goods
consumed
Total utility Marginal utility
1 10 -
2 16 A
3 B 4
4 20 C
THE LAW OF DIMINISHING MARGINAL UTILITY
The law of diminishing marginal utility states that, other things being equal, the marginal
utility of a commodity to an individual decreases with extra unit of that commodity he
consumes. In other words, the law states that if a consumer goes on consuming
successive equal increments in the quantity of a commodity, then the increase in total
utility resulting will become smaller and smaller, that is, satisfaction per extra unit will
start falling.
UTILITY MAXIMIZATION
Utility maximization is also known as equilibrium of the consumer. A point where a
consumer derives maximum satisfaction when his marginal utility equates the price of the
commodity consumed. That is, the additional utility derived from the consumption of
additional commodity is equal to price of the commodity. Alternatively, a consumer’s
utility is maximized when the MU per amount spent on a product is equal to the MU per
amount spent on any other product, as stated below:
MUx MUy MUz
Px = Py = Pz.

where MUx = MU of commodity X
Px = Price of commodity X
MUy = MU of commodity Y
Py = Price of commodity Y
MUz = MU of commodity Z
Pz = Price of commodity Z
CONSUMER SURPLUS
Consumer surplus is define as the difference between the amount a consumer budgeted to
pay for a commodity based on the anticipated level of satisfaction, and the amount he
actually paid to have it. When he consumed the first unit, he was willing to pay as much
as #50, but the commodity’s price was #30. Thus, he saved #20.Therefore any amount
above the market price of #30 represents the consumer’s surplus.
EVALUATION
1. Define consumer surplus.
2. State the law of diminishing marginal utility.
3. Use the tale below to answer the following questions:
PLATE OF RICE CONSUMED TU MU
0 0 0
1 100 100
2 160 ?
3 ? 40
4 ? 10
5 230 ?
6 230 ?

7 200 ?
3(a). Complete the above utility schedule
(b). Draw the MU curve
(c)i At what quantity does MU equal TU?
ii What happens to the values of TU as quantity consumed increases?
iii What is the value of MU when TU is maximized?
Iv What happens to MU as the quantity consume increases?
READING ASSIGNMENT
Read Essential Economics page 176 to 177 by C.E. ANDE
1. Why is scarcity a fundamental problem?
2. Define labour.
3. Differentiate between implicit cost and explicit cost.
4. What is mobility of labour?
5. List four advantages of the mean
WEEKEND ASSIGNMENT
1. Which one of these assumptions do economists always make about consumers?
(a) That they are all wage earners (b) That they make rational decisions in the
market (c) That they cannot spend more than their incomes (d) That they can
measure utility derived from consumption
2. The aim of the consumer in allocating his income is (a) to maximize his marginal
utility (b) to buy goods he wants most whatever the price. (c) to maximize his total
utility (d) to buy those goods which fallen in price.

3. ........................takes place when the ratio MU of a commodity consumed is equal
to the ratio of its price (a) consumer surplus (b) law of diminishing marginal utility
(c) consumer behaviour (d) utility maximization
4. Total utility (TU) attains its peak when the Marginal utility (MU) is ..... (a) zero on
x- axis (b) above x- axis (c) close to x – axis (d) under x- axis
5. The difference between the amount of money a consumer planned to pay for a
commodity and the actual amount of money he paid is.......... (a) commodity price
(b) consumer surplus (c) marginal cost (d) producer surplus
6. Which of these does not relate to the law of comparative advantage? (a) the law o
comparative advantage was propounded by David Ricardo (b) The law stresses the
importance of relative efficiency ( C) In order to specialize, a country must have
absolute advantage (d) The law is based on opportunity cost (e) The principle if
followed should increase total World output.
7. A condition which adversely affects expansion of production is (a) effective
management (b) limited size of the market (c) availability of funds (d) increase
profit prospects (e) increase return to scale.
8. international trade and domestic trade are similar in all aspects except (a)
transportation by land, water, and air is involved (b)goods are exchanged (c)
services are exchanged (d) the same currency is used as medium of exchange (e)
specialization and increased consumption is encouraged.
9. the drawer of cheque is the (a) the person who is to be paid the sum of money as
written on the cheque (b)person who take the cheque to the bank. ( C) bank on
which the cheque is drawn. (d) person who write out the cheque. (e) bank official
who certifies the payment.
10. which of the following is not an item of capital expenditure? (a) Building of roads
and bridges (b) Supply of electricity (c) Building of dams (d) Building of harbours
(e) Payment of interest on loans.
THEORY

1. With the use of table, explain the concept of diminishing marginal utility.
2. Explain how utility is maximized.
3. Discuss five contribution made by agriculture to the industrial development of
your country.
4. Explain the factors that affect the supply of labour in Nigeria.
5. A. Define a market
B. Explain four characteristics of a perfect market.

Subject Economics
Week 4
Class Ss2
topic THEORY OF DEMAND AND SUPPLY
WEEK FOUR
DEMAND AND SUPPLY
CONTENT
 Change in Quantity Demanded
 Change in Demand
 Change in Quantity Supplied
 Change in Supply
 Effects of change in demand and supply on equilibrium price and quantity
CHANGE IN QUANTITY DEMANDED
A change in quantity demanded, is otherwise known as movement along a particular
demand curve that is only influenced by price. When there is a change in the quantity
demanded, the demand curve does not shift. This is because the price of the commodity is
the only cause of a change in the quantity demanded while other factors remain
unchanged.

Price
D
10
5
0 D
x
20 30
Quantity
Change in Quantity Demanded
From the above diagram, as the price falls from #50 to #30, the quantity demanded
increases from 60 to 80 units,
Hence movement along the same demand curve took place from A to B.
Further decrease or increase in price will also affect the movement along the same
demand curve.
CHANGES IN DEMAND
When different quantities of goods and services are demanded at a particular price, it is
called a change in demand. It is caused by those factors that generally affect the demand
of a commodity other than the price of the commodity. For example changes in taste and
fashion, changes in income etc Change in demand shows a shift of the demand curve to
an entirely new position. A shift of the demand curve to the right is termed an increase in
demand while a shift of the demand curve to the left is a decrease in demand.

Price
D1 D2
D2
D1
Q1 Q2
Quantity
(i) Increase in Demand
Price
D1 D2
N10
D1
Q1 Q2
Quantity
D2

(ii) Decrease in Demand
EVALUTION
1. State three factors responsible for the change in demand.
2. What is change in quantity demand?
CHANGES IN QUANTITY SUPPLIED
Change in quantity supplied is only influenced by price. It involves movement along the
same supply curve
y
Price S
P2
P1
S
x
Q1 Q2
Quantity
Change in Quantity Supplied

CHANGE IN SUPPLY
Change in supply is caused by factors other than the price of the commodity. It involves a
bodily shift of the supply curve either to the right (increase in supply) or to the left
(decrease in supply
Price Price
P
Q2 Q0 Qty
Qo Q1 Qty (ii) Decrease in supply
(i)Increase in supply
EVALUATION
1. What is change in quantity supplied?
2. State the factors responsible for change in supply.
EFFECTS OF CHANGES IN DEMAND AND SUPPLY ON EQUILIBRIUM
PRICE AND QUANTITY
Changes in demand and supply lead to a change in the equilibrium price. Once there is
any change in either demand or supply, the initial equilibrium will be disrupted and a new
equilibrium will be created. The market equilibrium price can be affected in the following
ways.
So S1
1
So
S1
S2 S0
S2
So

1. Increase in Demand
Price
D2
D1 S
P2
P1
S D2
D1
Q1 Q2 Quantity
Effects of increase in demand
a. Increase in the equilibrium price from P1to P2
b. Increase in the equilibrium quantity from Q1 toQ2

2. Decrease in Demand
Price D1 D2 S
P1
P2
S D1
Q2 Q1 Qty
Effects of Decrease in Demand
a. Decrease in the equilibrium price from P1 to P2
b. Decrease in the equilibrium quantity from Q1to Q2
D2

3. Increase in Supply
S1 S2
Price
P1
P2
S1 S2
D
Q1 Q2
Quantity
Effects of Increase in Supply
a. Decrease in the equilibrium price from P1 to P2
b. Increase in the equilibrium quantity from Q1to Q2
4. Decrease in supply
Price
P2
P1
S1
Q2 Q1
Quantity
Effects of Decrease in Supply
a. Increase in the equilibrium price from P1 to P2
D
S2
D
D
S2
S1

b. Decrease in the equilibrium quantity from Q1to Q2
EVALUATION QUESTION
1) What is the equilibrium quantity?
2) Illustrate with a diagrammatic sketch the market situation at a price lower than the
equilibrium price”
3) Explain with the aid of diagrams how the market equilibrium price is affected by
the combined effects of:
a. Increase in demand and increase in supply.
b. Decrease in demand and decrease in supply.
c. Increase in demand and decrease in supply.
READING ASSIGNMENT
Amplified and Simplified Economic for SSS by Femi Longe page 290--296
Fundamentals of Economics by Anyawuocha page 166-168
1. Distinguish between fixed cost and variable cost.
2. Under what condition will a perfectly competitive firm maximize profit.
3. Describe each of the following;
(a) abnormal demand ( b) Effective demand
4. What is a public corporation.
5. Explain the causes of a declining population.
WEEKEND ASSIGNMENT
1. At the equilibrium price, quantity demanded is (a) greater than quantity supplied
(b) equal to quantity supplied (c) less than quantity supplied (d) equal to excess
supply

2. If the government fixes a price of a commodity above the equilibrium price, the
quantity supplied will be (a) less than the quantity demanded (b) equal to the
quantity demanded (c) greater than the quantity demanded (d) equal to zero
3. The market price of a commodity is normally determined by the (a) law of demand
(b) interaction of the forces of demand and supply (c) total number of people in
the market (d) total quantity of the commodity in the market
4. The gap between demand and supply curves below the equilibrium price indicates
(a) excess demand (b) excess supply (c) equilibrium quantity (d) equilibrium price
5. If prices fall below the equilibrium (a) demand will equal supply (b) demand will
be greater than supply (c) supply will be greater than demand (d) quantity
supplied will be zero
SECTION B
1. Given the demand and supply function for a crate of eggs as follows:
Qd = 12 –2p; Q = 3+1p
Determine the equilibrium price and quantity
2. What is the excess supply at the price of N3.50?

CAVENDISH COLLEGE LESSON NOTE FOR FIST TERM YEAR11
Subject Economics
Week 5
Class Ss2
Topic Elasticity of Demand
WEEK FIVE
ELASTICITY OF DEMAND
CONTENT
 Definition of Elasticity of Demand
 Types of Elasticity of Demand
 Price Elasticity of Demand
 Types of price elasticity of demand and graphical representation
 Factors affecting elasticity of demand
DEFINITION OF ELASTICITY OF DEMAND
Elasticity of demand may be defined as the degree of responsiveness of demand to a little
changes in price of a commodity.
Types of Elasticity of Demand
1. Price elasticity of demand
2. Income elasticity of demand

3. Cross elasticity of demand
EVALUATION
1. Define Elasticity.
2. State three types of Elasticity of demand.
PRICE ELASTICITY OF DEMAND
Price elasticity of demand also known as the co-efficient of price elasticity, may be
defined as the degree of responsiveness of demand for a particular commodity to changes
in its price. It is the rate at which the quantity demanded changes as its price changes.
To measure price elasticity of demand we use the formula:
% change in Quantity Demanded
% change in price
This formula can be broken down or simplified as:
Old Quantity – New Quantity X 100
Old quantity
E= Old Price – New Price X 100
Old Price
Illustration
When the price of a given product is reduced from N90 to N80, the quantity demanded
increases from 50 to 60 units. Deduce the co-efficient of elasticity of demand.
Solution
Old price = N90, New price = N80
Change in price = 80 – 90 = -10
= 10 x 100
90 1 = 11.1%
Old quantity = 50, New quantity = 60
Change in quantity = 60 – 50 = 10

= 10 x 100
50 1 = 20%
PE = 20
11.1 = 1.8%
TYPES OF PRICE ELASTICITY OF DEMAND
The types of elasticity of demand and their graphical representation can be shown as
follows:
1. Perfectly Elastic (or Infinitely Elastic) Demand.
Consumers react sharply to changes in price. They are willing to buy all the goods
available at a particular price and none at all at a slightly higher price. The co-efficient of
elasticity tends to infinity.
Price
D
Quantity
2. Perfectly Inelastic (or Zero Elasticity) Demand
When the quantity demanded remains the same regardless of the change in price. The
demand is said to be perfectly inelastic. The co-efficient of elasticity is zero
Price
D
D
Quantity

3. Unitary (or Unity) Elasticity of Demand
This is the situation where a change in price or income brings about the same percentage
change in the quantity demanded. The co-efficient of elasticity of demand is equal to 1
Price
D
P2
P1
Q1 Q2
Quantity
4. Fairly Elastic Demand or Elastic Demand
In this case a small percentage change in price gives rise to more than proportionate
change in the quantity demanded. For example where a 20% fall in price leads to 50%
rise in demand, the co-efficient of elasticity is greater than 1 but less than infinity.
Price
D
P1
P2
D
Q1 Q2
Quantity
5. Inelastic Demand (Fairly Inelastic Demand)
D
Quantity

When a change in price of a commodity leads to a less than proportionate change in the
quantity demanded then demand is inelastic e g a 15% increase in price bringing about
10% decrease in quantity demanded.
The co-efficient of elasticity is less than 1 but greater than zero
Price
D
P2
P1
D
Q1 Q2
Quantity
FACTORS AFFECTING (OR DETERMINING) ELASTICITY OF DEMAND
1. Availability of Close Substitutes: A commodity that has close substitutes is
likely to have an elastic demand
2. Degree of Necessity of the Goods: If a commodity is a necessity or a near-
necessity, increase or decrease of its price are not likely to affect its demand
3. Proportion of Consumer’s Income that Is Spent on that Commodity:
Generally the higher a persons income, the more inelastic his demand for
commodities

4. Habit: If a consumer has become addicted to a commodity, his demand for the
good will tend to be monastic. An increase in the price of the commodity may
therefore not affect (reduce) his quantity demanded.
5. The Level of Consumer’s Income: The larger the income of the consumer the
more inelastic is his demand for commodities. On the other hand, the demand of
consumers with low income tends to be elastic.
6. Cheap Commodities: The cost of some commodities are relatively insignificant
and as such consumers demand for them will be inelastic.
EVALUATION
1. Define price elasticity of demand.
2. The figure below was-extracted from the demand schedule of Kingsley Nanta, a
consumer of bread.
Price in naira Quantity Demanded
Old New Old New
50 70 200 160
You are required to calculate:
i. Percentage change in quantity demanded
ii. Percentage change in price
iii. Co-efficient of price elasticity of demand
iv. From your answer in i-iii above state whether demand is elastic or inelastic.
v. Explain your answer in (c) above.
3. With the aid of sketch diagrams explain the following types of elasticity demand
(a) Unity (b) Inelastic (c) Elastic (d) Zero (e) Infinitely.
READING ASSIGNMENT

1. Comprehensive Economics by J.U Anyaele page 124-127
2. Fundamentals of Economics by Anyanwuocha page 227-236
1. What is abnormal demand?
2. High the importance of opportunity cost to the government.
3. Explain three differences between public corporation and public limited liability
company.
4. Distinguish between peasant farming and commercial farming.
5. Why is scarcity a fundamental problem in Economics?
WEEKEND ASSIGNMENT
1. If elasticity of supply is greater than 1 supply is (a) Unitary elastic (B) Inelastic (c)
Elastic (d) Infinitely elastic
2. When the demand curve is a straight line parallel to x axis, demand is (a) fairly
elastic (b) fairly inelastic(c) Perfectly elastic (d) Perfectly inelastic
3. If elasticity of demand for a commodity is less than 1, demand is (a) Unitary
elastic (b) Inelastic (c) Infinitely elastic (d) Zero elastic
4. If the price of a commodity rises from N2 o N4 and its demand decrease from 125
to 100 then the co-efficient of elastic of demand is (a) 0.02 (b) 0.20 (c) 0.25 (d) 5
5. For a good having close substitutes the price elasticity of demand is likely to be (a)
Zero (b) negative (c) more than (d) less than
SECTION B
1. Define elasticity of demand.
2. State three factors that determine the elasticity of demand for goods.

CAVENDISH COLLEGE LESSON NOTE FOR FIRST TERM ECONOMICS SSS2 UPDATED..docx

Subject Economics
Week 6
Class Ss2
Topic Elasticity of Demand
WEEK SIX
ELASTICITY OF SUPPLY
CONTENT
 Meaning of Elasticity of Supply.
 Formula for Calculating Elasticity of Supply.
 Graphical Illustration of Elasticity of Supply.
DEFINITION - Elasticity of supply can be defined as the degree of responsiveness of
change in quantity supplied as a result of change in price. Elasticity of supply measures
the extent to which the quantity of a commodity supplied by a producer changes as a
result of a little change in the price of the commodity.
MEASUREMENT OF ELASTICITY OF SUPPLY – Elasticity of supply can be
measured or calculate by using the co-efficient of price elasticity of supply. The
formula used in calculating the elasticity of supply is :
Elasticity of supply (ES) = % change in supply
% change in price = %∆QS
% ∆P
where ∆ = Change
QS= Quantity Supply

P = Price
% = Percentage
The table below shows the relationship between prices of goods and the unit of
commodity supplied.
Price (N) Quantity Supplied
9 850
10 1000
11 1,150
1. Calculate the elasticity of supply when price falls from N10.00 to N9.00
State whether the supply in (iii) above is elastic or inelastic (WASSCE
1994)
New Qty - Old Qty x 100
Old Qty 1
Old Quantity = 1000
New Quantity = 850
New – Old x 100
Old 1
850 - 1000 x 100
1000 1
150 x 100 = 15%
1000 1
Old Price = N10
New Price = N9
New Price – Old Price x 100
Old Price 1
9 – 10 x 100 = 1 x 100 = 10%

10 1 10 1
Elasticity of Supply = 15 = 1.5
10
EVALUATION
1. Define elasticity.
2. State the formula for calculating price elasticity
TYPES OF ELASTICITY OF SUPPLY
1. Perfectly (Zero) Inelastic Supply: Supply is said to be perfectly inelastic if a
change in price has no effect whatsoever on the quantity of commodity supplied.
In this case, elasticity is equal to zero, E = 0
Price S
10
5
O Q1 Qty
2. Fairly elastic Supply: Supply is said to be elastic, if a small change in price leads
to a greater change in the quantity of goods supplied. In this case, elasticity is
greater than one or unity E > 1.

Price S
10
5
S
O 10 12 Qty
3. Unity or Unitary Elastic Supply: Supply is said to be unitary when a change in
price leads to an equal change in the quantity of goods supplied. In other words, a
5% change in price will equally lead to a 5% change in supply. In this case,
elasticity of supply is equal to one, E = 1.
Price S
10
5
S
0 Q1 Q2
4. Fairly Inelastic Supply: Supply is said to be fairly inelastic if a large change in
price leads to a smaller or slight change in the quantity of commodity supplied.
In this case, elasticity is less than one but greater than infinity, E > 0 < 1
Price S
10
5
S
O 25 30 Qty

5. Perfectly ( Infinitely ) Elastic Supply: Supply is said to be perfectly elastic when
a change in price brings about an infinite effect on the quantity of goods supplied.
In other words, a slight increase in price can make producer to increase the supply
of the commodity, while a slight decrease in price will make producer to stop the
supply of the commodity. In this case, elasticity is equal to infinity, E = o0.
Price
5 S
O 10 15 20 Qty
FACTORS AFFECTING ELASTICITY OF SUPPLY
1. Cost of Production: The low cost of production normally results in elastic supply,
and while the high cost of production results in inelastic supply.
2. Nature of Goods: While durable goods are inelastic due to their nature,
perishable goods are elastic in supply.
3. Cost of Storage: Producer will supply all their goods to the market if the cost of
storage is very thereby making the supply to be elastic, and vice – versa.
4. Time: This relates mainly to agricultural produces which remain for a long time in
the farm before they are harvested. Before their harvest, their supply is inelastic
but after harvest, it becomes elastics.
5. Market Discrimination: Elasticity of supply of a commodity depends on where it
is sold. When few commodities are sold at a particular location as a result of lower

price, such commodity can be taken to another location where the price are higher.
In this case, supply is elastic and vice – versa.
6. Availability of Storage Facilities: The availability of storage facilities leads to
inelastic supply after harvest, while non – availability of storage facilities leads to
elastic supply.
EVALUATION
1. Define price elasticity of supply
2. State the formula for calculating price elasticity
READING ASSIGNMENT
1. Essential ECONOMICS PAGE 53 -56 BY C.E. ANDE
2.
1. Explain any five reasons why a joint stock company is preferable to a one – man
business.
2. Why are the small scale traders important in West Africa?
3. Distinguish between: (a) want and demand, (b) economic resources and non –
economic resources
4. What is unemployment?
5. Explain any three types of unemployment.
WEEKEND ASSIGNMENT
1. If the co-efficient of elasticity of supply is 0.3, then the supply is........... (a) fairly
inelastic (b) perfectly elastic (c) fairly elastic (d) perfectly inelastic
2. Price elasticity of supply measures the responsiveness of quantity supplied to....
(a) changes in suppliers’ income (b) changes in prices of other commodities (c) a
change in the price of the commodity (d) a change in the demand for the product

3. The price elasticity co-efficient indicates...... (a) how far business can reduce cost
(b) the degree of competition (c) the extent to which supply curve shifts (d)
consumer responsiveness to price changes
4. The equilibrium price of mangoes is #100. If the price falls to 50k, there will
be........... (a) an excess supply (b) no seller in the market (c) a shortage in supply
(d) a surplus in the market
5. When the price of a given commodity falls from #100 to #90, the quantity
supplied reduces from 60 to 50 units. From this, we can conclude that the
product’s......... (a) supply is elastic (b) supply is inelastic (c) supply is perfectly
inelastic (d) supply is perfectly elastic
SECTION B
1. What is price elasticity of supply?
2. State the formula for the calculation of the coefficient of price elasticity of supply

CAVENDISH COLLEGE LESSON NOTE FOR FIRST TERM ECONOMICS SSS2 UPDATED..docx

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