1. Cross-Price Elasticity of Demand
XED
Cross-Price Elasticity of Demand

2. Cross Price Elasticity -XED
This second type of elasticity measures the responsiveness of consumers of a particular good to a change in the price of a related good.”
Cross Price Elasticity -XED

3. The XED Coefficient The formula: XED = %ΔQA %ΔPB
%ΔQA is the percentage change in quantity of good A.
%ΔPB is the percentage change price of good B.
The XED Coefficient

4. Compliments and Substitutes
XED tells us how much demand will increase for a good when the price of a compliment falls. We will see the coefficients as negative – meaning there is a complementary relationship.
XED measures how much demand for a good decreases when the price of a substitute falls. We will see the coefficient as positive – meaning there is substitution relationship
Compliments and Substitutes

5. XED VALUES AND THE STRENGTH OF THE RELATIONSHIP BETWEEN PRODUCTS
The range of values is important. The sign tells us the relationship between the goods.
If the value of XED is positive, then goods are substitutes for each other, e.g. Coke and Pepsi.
The larger the value, the closer the relationship.
If the value of XED is negative, then goods are complements for each other, e.g. DVD players and DVDs.
If the value of XED is zero, then the goods are unrelated, e.g. strawberries and mobile phones.
Page 54 in Blue Book
XED VALUES AND THE STRENGTH OF THE RELATIONSHIP BETWEEN PRODUCTS

6. Why is it important? Firms need to be aware of XED –
To help them understand competitor’s price changes and the effect on demand
To be aware of their own complementary goods and the effect on one price change versus their other products.
Why is it important?

7. The HOMEWORK!
Trade and grade!

8. The Answers:
8. XED= % change in the quantity of one good over % change in the price of a related good. Therefore,
XED=-5/15 = Since the XED is negative, the good must be complements. An example of complementary goods is charcoal and charcoal barbeques. If the charcoal prices rise, we would expect barbeque sales to fall. (2 marks)
9. ( )/600 = 0.67/-0.2 =-3.35
(20-25)/25
The two goods must be complementary goods, because the XED coefficient is negative. An example is footballs and football shoes. The two goods in this example are cross-price elastic, since the absolute value of the XED coefficient is greater than one. (2 marks)
= %ΔQ = %ΔQ/0.25
(5-4)/4
To find the % change in tennis rackets, simplify the equation:
-0.8x 0.25 = So a 25% increase in the price of tennis balls led to a decrease in demand for tennis rackets of 20%. (2 marks)

9. Camel Demand Soars in India – A Case Study
Camels and oil related? XED Coefficient?
We should see a substitute relationship. Like hybrid cars replace gas guzzling SUVs in the USA, camels in India can replace gas guzzling tractor for farming. Because it is a substitute relationship there would positive coefficient value (2 marks)
Cross Price elasticity for camels and oil when oil rises ($110-$130) and quantity of camels increase from 250, 000 to 350,000.
(+100,000/250,000) x 100= 40% 40% = +2.22
( +20/$110) x % 18%
Oil price increases 18%, and during same time period quantity of camels increase by 40%. There is a substitute relationship going on.
(2 marks)
Other factors that may affect camels as the “beast of burden”.
Life span and health of camels – their food is not abundant.
Lifestyle of people
Other uses for camels that may affect it as a farm work substitute for tractors (or other oil using equipment
Tractors that don’t run on oil? (2 marks)

10. Income Elasticity of Demand
“YED”

11. Income Elasticity of Demand-YED
Income elasticity of demand is a measure of how much the demand for a product changes when there is a change in the consumer’s income.”
Income Elasticity of Demand-YED

12. The YED Coefficient The formula: YED = %ΔQd of the product
%Δ in income of the consumer
The YED Coefficient

13. The Range of Values for Income Elasticity of Demand
The sign tells us the type of good that is being considered.
Necessity goods are products that have low-income elasticity, essential products, e.g. bread.
Superior goods are products that have high-income elasticity, non-essential products, e.g. foreign holidays.
Inferior goods are products that have negative income elasticity, because the demand decreases as income increases, e.g. cheap wine or non-brand name jeans.
Page 55 in Blue Book
The Range of Values for Income Elasticity of Demand

14. The Range of Values for Income Elasticity of Demand
The range of values is important.
For normal goods, the value of YED is positive, i.e. as income increases the demand for the good increases.
If the value is between zero and 1, then the YED is said to be income inelastic.
If the value is greater than 1, then the YED is said to be income elastic.
NOTE: Engel Curve Figure 4.9 (potatoes fall as income of a country rises – instead they want pasta!)
Page in Blue Book
The Range of Values for Income Elasticity of Demand

15. Homework for Wednesday
Page 54 Workpoint 4.5
Page 56 Workpoint 4.6
Read over pp 56-61
Page 61 – “You be the journalist”
Write and submit a typed article regarding the Headline listed , the economic concept and the suggested diagram.
(refer to p 17 if you need an example of how to do this!)