How is a consumer's demand curve derived from the consumer choice model?

The demand curve for a consumer is derived by examining how the quantity demanded of a good changes as its price varies. This process involves keeping other factors constant, such as the consumer's income and preferences, to isolate the effect of price changes on quantity demanded. By systematically lowering or raising the price of the good and observing the corresponding quantity demanded, one can indeed plot a downward-sloping demand curve. This reflects the law of demand, which states that all else being equal, as the price of a good decreases, the quantity demanded increases, and vice versa.

In contrast, considerations of varying the prices of all goods or varying income while holding prices constant would not accurately depict the unique relationship between price and quantity demanded for a specific good. Similarly, varying consumer preferences without adjusting the price of the good would not yield a standard demand curve. Thus, focusing solely on the price of the good while observing changes in quantity purchased succinctly captures the demand behavior that forms the basis of the consumer demand curve.