The price-taker model (every paper)

NZ is too small to affect the world price, so Pw is a horizontal line. The gap between domestic supply and demand AT that price is the export or import quantity.

Reading the graph

Pw is drawn horizontal — NZ accepts the world price, it cannot change it.
At Pw, domestic quantity SUPPLIED (Qs) and quantity DEMANDED (Qd) are read off the NZ supply and demand curves.
If Qs > Qd at Pw, NZ EXPORTS the difference (X = Qs − Qd).
If Qd > Qs at Pw, NZ IMPORTS the difference (M = Qd − Qs).
A world-price CHANGE shifts Pw itself, which changes Qs and Qd along the existing curves — the curves do not move.

Exam-style World lamb price falls Show the impact on NZ lamb exports, and on producers vs consumers. Pw falls to a new, lower horizontal line. At the lower price, NZ producers supply LESS (move down the SNZ curve) and NZ consumers demand MORE (move down the DNZ curve). The export gap (Qs − Qd) shrinks, so export volume AND export receipts both fall. NZ producers are worse off (lower price, lower revenue); NZ consumers of lamb are better off (cheaper lamb at home). ✓ Lower world price → smaller export gap → producers lose, consumers gain — a genuine winners-and-losers question, not a one-sided one.

Total spending vs quantity — a common trap

Quantity purchased is just the amount bought; total spending = quantity × price — a price fall can raise quantity but still lower or raise total spending depending on how much quantity responds.

Practice for this standard covers the whole topic — flashcards and quiz.