If we observe that when consumers' incomes rise by 10%, the quantity demanded of ice cream increases by 5%, then ice cream is an inferior good.

Inferior Good

A type of good whose demand decreases when consumer income rises, unlike normal goods, for which demand increases with income.

Quantity Demanded

The amount of a product consumers are willing and able to purchase at a given price over a specified time period.

Income

The money received by an individual or business for work done, from investments, or from the sale of goods or services.