Intro_to_microeconomic_2

goal part2

  • Supply and demand(15%–20%)
    • 1.Market equilibrium
    • 2.Determinants of supply and demand
    • 3.Price and quantity controls
    • 4.Elasticity
      • a.Price, income and cross-price elasticities of demand
      • b.Price elasticity of supply
    • 5.Consumer surplus, producer surplus and market efficiency
    • 6.Tax incidence and deadweight loss

Market equilibrium市场均衡

  • equilibrium
    • 在市场上，市场供求达到平衡时的状态
      • ​A state of balance between the opposing forces of shortages and surpluses盈餘
    • equally divide the property to all the society member
  • efficiency
    • the maximum property that the society can get from limited resources
  • sometimes we need to balance the income of the rich and poor
    • but this will reduce the stimulation of produce and work
      • and make the limited resource fewer
  • 消费者和生产者根据市场价格决定愿意并且能够购买或者能够提供的商品数量，带着各自的盘算，消费者与生产者一起进入市场，最终决定市场的均衡。
  • 市场均衡图由横纵两条坐标轴和供求两条曲线构成。横坐标代表数量quantity，纵坐标代表价格price。需求曲线是向右下方倾斜的一条直线，反映需求量quantity demanded和价格之间的关系；供给曲线是向右上方倾斜的一条直线，反映供给量quantity supplied和价格之间的关系。曲线相交点代表市场均衡点，即在这个价格下，生产的产品刚好被买走。

Determinants of supply and demand

  • 影响商品供求关系的非价格因素的变动对价格和产量的影响我们称之为供求定理

  • Determinants of Demand

    • ​Price of the product
      • primary determinant
      • doesn’t cause the demand curve to shift, but a change in the quantity demanded
      • all other determinants can cause the demand curve to shift, a “decrease/increase in demand”
    • Income
    • Consumer tastes
    • Prices of substitute products
    • Prices of complementary products
    • Expected future price of the product

  • Determinants of Supply

    • Price of the product
      • a change in price is a ‘change in the quantity supplied’
      • a change in anything else, ‘change in supply,’ shifts the supply curve
    • Prices of inputs required to make the product
    • Technology and productivity
    • Expected future price of the product

  • 需求变动对市场均衡的影响

    • 需求增加引起均衡价格上升，需求减少引起均衡价格下降。
    • 需求增加引起均衡产量增加，需求减产引起均衡产量减少。
    • 需求的变动引起均衡价格与均衡产量同方向变动。
  • 供给变动对市场均衡的影响
    • 供给增加引起均衡价格下降，供给减少引起均衡价格上升。
    • 供给增加引起均衡产量的增加，供给减少引起均衡产量的减少。
    • 供给的变动引起均衡价格反方向变动，供给的变动引起均衡产量同方向变动。
  • Supply and demand affect each other indirectly, not directly
  • 正常物品的需求和收入成正比
    • 收入增加会增加每种价格水平下的需求量，并且使得需求曲线向右移动
    • 低档物品的需求和收入成反比，收入增加会使低档物品的需求曲线向左移动
  • 替代品：一种物品价格的上升引起另外一种物品需求量增减的两种物品
  • 互补品：一种物品价格上升引起梁歪一种物品需求量减少的两种物品
  • 嗜好：对一种物品的嗜好的增加会使那种物品的需求增加，并且使得他的需求曲线向右移动

Price and quantity controls

  • 政府价格和市场调控
  • price control are legal restriction on how high or how low a market price may go
    • price ceilings价格天花板
      • 设定在市场均衡价格之下，导致供不应求
      • a maximum price sellers are allowed to charge for a good or service
      • decreases supply
      • established under the equilibrium price
    • price floors价格地板
      • 设定在市场均衡价格之上，导致供过于求。
      • a minimum price buyers are required to pay for a good or service
      • established above the equilibrium or market price
      • causes a surplus to develop

Elasticity彈性

Price, income and cross-price elasticities of demand

  • 需求的价格弹性:用来衡量需求的数量随商品的价格的变动而变动的情况
    • 通常来说，因为商品价格的下跌会导致需求数量的增加，所以一般情况下需求的价格弹性系数为负数。
    • 注意以絕對值比較彈性強弱
      • Ed 的數值是負數，因為價格與需求量是反向關係 (negative relationship)。在比較 elasticity 的強弱時，是不理會數值前的「負號」的，即是只看 Ed 的絕對值 (absolute value) ，絕對值愈大，所代表的彈性愈大。
    • 彈性是以價格和需求量的改變率計算的
      • 例如 Good A 和 Good B 的價格同時上升 $5，而需求量同時下降 8，但由於改變率不同，得出的彈性也就不同。
    • 影响因素
      • 替代品的多寡
      • 该物消费支出占总所得的比例
      • 物品耐用性
      • 必需品或奢侈品
      • 商品的定义范围
      • 时间的长短

Price elasticity of supply

  • 供給的價格彈性(供給彈性):表示價格變動1%引起供給量變動的程度
  • 根據經濟學中的供給定理，供給量與價格是同方向變動的，即該商品的價格變動的越大，企業的生產就會隨之變化。
  • 供給的價格彈性可以根據es值的大小分為五種類型。es>1表示供給富於彈性；es＜1表示供給缺乏彈性；es=1表示供給單一彈性或單位彈性；es=∞表示供給完全彈性；es=0表示供給完全無彈性。
  • 影响因素
    • 增加產量所需追加生產要素費用的大小。一般地說，若增加產量的投資費用較小，則供給彈性大；反之供給彈性小。
    • 時間的長短
      • 一般在短時期內，廠商只能在固定的廠房設備下增加產量，因而供給量的變動有限，這時供給彈性就小。在長期內，廠商能夠通過調整規模來擴大產量，這時供給彈性將大於同種商品在短期內的供給彈性。

Consumer surplus, producer surplus and market efficiency

  • A market is efficient when it provides the most consumer surplus and the most producer surplus possible. An inefficient market creates what economists call a deadweight loss.
  • Consumer surplus
    • the difference in the market price of a good and how much an individual or individuals would be willing to pay
      • 消费者剩余=支付意愿–市场价格
      • for example
        • a person who is willing to spend $4 on a milk shake but the price is only $3 yielding a surplus of $1.
  • producer surplus
    • for example
      • 生产者剩余=市场价格–生产成本
      • the difference between what it costs to produce a good and what price the market provides.
  • 消费者剩余=支付意愿–市场价格；生产者剩余=市场价格–生产成本

Tax incidence and deadweight loss税收负担和无谓损失

  • 无谓损失是市场扭曲引起的总剩余减少；弹性越大，税收的无谓损失越大。
    • 无谓损失又为社会净损失，是指由于市场未处于最优运行状态而引起的社会成本, 也就是当偏离竞争均衡时, 所损失的消费者剩余和生产者剩余

excercise

  • 1.What is the difference between a “change in demand” and a change in “quantity demanded.”

    • A change in demand需求变动 : to a change in the amount that consumers are willing to buy at every possible price, in term of the demand curve shifts.
    • A change in the quantity demanded数量需求变动 occurs when the price of the product changes. In this case, in terms of the demand curve, there is a movement along the demand one.

  • 2.What is the difference between a “change in supply” and a change in “quantity supplied.”

    • A change in supply供求变动 refers to a change in the amount that producers are willing to sell at every possible price, in terms of the supply curve, the supply curve shifts
    • A change in the quantity supplied供给数量 occurs when the price of the product changes. In this case, in terms of the supply curve, there is a movement along the supply curve.

  • 3.What does ceteris paribus mean? How does this relate to supply and demand analysis?

    • Ceteris paribus means “with other things the same”
    • By holding all other things constant, and allowing only one of these influences to change, we are able to determine its effect on supply or demand.

  • 4.Holding demand constant, what is the only thing that can cause a change in quantity demanded? What are the things that cause a change in demand?

    • the change in quantity demanded go up when the price of the good change
    • all the influence that cause a shift in the curve, may cause a change in demand– 5.How do changes in income affect the demand for a good?
    • Income changes cause the demand for a good to increase or decrease.
    • if the good in question is normal, an income increase(decrease) will cause the demand 次品”, an income increase will lower(increase) the demand for good.– 6.How do substitute and complementary goods affect the demand for a good.?
    • if the price of a 替代品 上升(下降), then the demand for the good in question will 上升(下降).
    • on the other hand, 如果补给品的价格上升(下降)，the demand for the good in question will下降(上升).
economic
Comments

Comments