Luxury Goods vs. Necessity Goods: YED Examples for AP Micro

📚 Quick Study Guide

• 💰 Necessity Goods: These are essential items consumers need, like food and basic clothing. Their demand doesn't change much with income.
• 💎 Luxury Goods: These are non-essential items that consumers buy when they have extra income, like designer clothing or fancy cars. Demand is highly sensitive to income changes.
• 📈 Income Elasticity of Demand (YED): Measures how much the quantity demanded of a good responds to a change in consumer income.
• ➗ YED Formula: $YED = \frac{\% \, Change \, in \, Quantity \, Demanded}{\% \, Change \, in \, Income}$
• 🔢 YED < 0 (Negative): Inferior Goods (as income rises, demand falls)
• ➕ 0 < YED < 1: Necessity Goods (income inelastic)
• 🚀 YED > 1: Luxury Goods (income elastic)

Practice Quiz

1. Which of the following goods is most likely to be a necessity good?
   1. Designer handbags
   2. Basic groceries
   3. Sports cars
   4. Luxury watches
2. If the income elasticity of demand for a good is 0.5, the good is considered:
   1. A luxury good
   2. A necessity good
   3. An inferior good
   4. A normal good with elastic demand
3. If an individual's income increases by 10% and their quantity demanded for organic food increases by 15%, what is the income elasticity of demand for organic food?
   1. 0.67
   2. 1.5
   3. -0.67
   4. -1.5
4. Which of the following YED values indicates a luxury good?
   1. -0.5
   2. 0.2
   3. 1.8
   4. 0
5. As incomes rise during an economic expansion, which sector tends to experience the largest percentage increase in sales?
   1. Utilities
   2. Basic Clothing
   3. Luxury Automobiles
   4. Staple Foods
6. A good with a negative income elasticity of demand is known as:
   1. A normal good
   2. A luxury good
   3. An inferior good
   4. A necessity good
7. If the income elasticity of demand for a good is 2.0, a 5% increase in income will lead to:
   1. A 2.5% increase in quantity demanded
   2. A 10% increase in quantity demanded
   3. A 2.5% decrease in quantity demanded
   4. A 10% decrease in quantity demanded