【正文】 an energy bar is a normal good, an increase in ine increases the demand for energy bars. Demand 169。 2020 Pearson AddisonWesley Figure shows a supply curve of energy bars. A rise in the price of an energy bar, other things remaining the same, brings an increase in the quantity supplied. Supply 169。 2020 Pearson AddisonWesley Figure shows an increase in supply. An advance in the technology for producing energy bars increases the supply of energy bars and shifts the supply curve rightward. Supply 169。 2020 Pearson AddisonWesley An Increase in Demand Figure shows that when demand increases the demand curve shifts rightward. At the original price, there is now a shortage. The price rises, and the quantity supplied increases along the supply curve. Predicting Changes in Price and Quantity 169。 2020 Pearson AddisonWesley Decrease in Both Demand and Supply A decrease in both demand and supply decreases the equilibrium quantity. The change in equilibrium price is uncertain because the decrease in demand lowers the equilibrium price and the decrease in supply raises it. Predicting Changes in Price and Quantity 169。 2020 Pearson AddisonWesley When demand decreases, the equilibrium price falls and the equilibrium quantity decreases. Predicting Changes in Price and Quantity 169。 2020 Pearson AddisonWesley Equilibrium is a situation in which opposing forces balance each other. Equilibrium in a market occurs when the price balances the plans of buyers and sellers. The equilibrium price is the price at which the quantity demanded equals the quantity supplied. The equilibrium quantity is the quantity bought and sold at the equilibrium price. ? Price regulates buying and selling plans. ? Price adjusts when plans don’t match. Market Equilibrium 169。 2020 Pearson AddisonWesley Prices of Factors of Production If the price of a factor of production used to produce a good rises, the minimum price that a supplier is willing to accept for producing each quantity of that good rises. So a rise in the price of a factor of production decreases supply and shifts the supply curve leftward. Supply 169。 2020 Pearson AddisonWesley If a firm supplies a good or service, then the firm 1. Has the resources and the technology to produce it, 2. Can profit from producing it, and 3. Has made a definite plan to produce and sell it. Resources and technology determine what it is possible to produce. Supply reflects a decision about which technologically feasible items to produce. The quantity supplied of a good or service is the amount that producers plan to sell during a given time period at a particular price. Supply 169。 2020 Pearson AddisonWesley Six main factors that change demand are ? The prices of related goods ? Expected future prices ? Ine ? Expected future ine and credit ? Population ? Preferences Demand 169。 2020 Pearson AddisonWesley The Law of Demand The law of demand states: Other things remaining the same, the higher the price of a good, the smaller is the quanti