Calculating YED: Definition and Example Calculations for UK Students

📚 Quick Study Guide

• 📈 Definition: Income Elasticity of Demand (YED) measures the responsiveness of the quantity demanded for a good or service to a change in consumer income.
• 🧮 Formula: YED = % Change in Quantity Demanded / % Change in Income. Mathematically, this is represented as: $YED = \frac{\% \Delta Q}{\% \Delta Y}$
• ➕ Positive YED: Indicates a normal good. As income increases, demand increases.
  • 🍎 Necessity (0 < YED < 1): Inelastic response to income changes (e.g., food).
  • 🚗 Luxury (YED > 1): Elastic response to income changes (e.g., designer clothes).
• ➖ Negative YED: Indicates an inferior good. As income increases, demand decreases (e.g., value brand products).
• 🇬🇧 UK Context: Consider how changes in average UK household income affect demand for various goods and services. For example, during periods of economic growth, demand for luxury cars tends to increase significantly.
• 📊 Calculation Example: If average UK incomes rise by 5% and the demand for organic vegetables increases by 8%, then YED = 8%/5% = 1.6 (a luxury good).

Practice Quiz

1. Which of the following best describes Income Elasticity of Demand (YED)?
   1. The responsiveness of quantity supplied to a change in price.
   2. The responsiveness of quantity demanded to a change in price.
   3. The responsiveness of quantity demanded to a change in consumer income.
   4. The responsiveness of quantity supplied to a change in consumer income.
2. If a good has a YED of -0.5, what type of good is it?
   1. Normal good
   2. Luxury good
   3. Inferior good
   4. Necessity
3. If average UK household income increases by 3% and the demand for designer handbags increases by 9%, what is the YED for designer handbags?
   1. 0.33
   2. 3
   3. -3
   4. -0.33
4. A YED value of 0.8 indicates which type of good?
   1. Inferior good
   2. Luxury good
   3. Necessity
   4. Giffen good
5. During a recession in the UK, average incomes fall by 4%. If the demand for value-brand pasta increases by 6%, what is the YED for value-brand pasta?
   1. 1.5
   2. -1.5
   3. 0.67
   4. -0.67
6. Which of the following goods is most likely to have a high positive YED?
   1. Basic food staples
   2. Generic medicine
   3. Luxury holidays
   4. Second-hand clothing
7. If the YED for good X is 2.5, what does this indicate?
   1. Good X is an inferior good.
   2. Good X is a necessity.
   3. Good X is a luxury good and demand is highly responsive to income changes.
   4. Good X is income inelastic.