Final answer:
The income effect causes Corey's quantity demanded of a frozen dinner to increase when the price of a frozen dinner increases.
Step-by-step explanation:
The effect that causes Corey's quantity demanded of a frozen dinner to increase when the price of a frozen dinner increases is known as income effect.
The income effect occurs when a price change leads to a change in the purchasing power of consumers.
In this case, as the price of a frozen dinner increases, Corey's real income decreases, making frozen dinners relatively more affordable compared to healthier food, causing him to increase his quantity demanded of frozen dinners.