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1、copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.* of 403.1consumer preferences3.2budget constraints3.3consumer choice3.4revealed preference3.5marginal utility and consumer choice3.6cost-of-living indexesc h a p t e r 3prepared by:fernando quijano, illustratorconsumer beha

2、viorchapter outline2 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.第三章第三章 消費者行為消費者行為consumer behavior 3 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.第三章第三章3.1 消費者偏好3.2 預(yù)算約束3.3 消費者選擇3.4 顯示偏好3.5 邊際效益與消費者選擇3.6 生活成本指數(shù)4 of 40copyright

3、 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.消費者行為消費者行為理論消費者行為理論 描述消費者如何在不描述消費者如何在不同的商品和服務(wù)之間分配其收入以使幸福最同的商品和服務(wù)之間分配其收入以使幸福最大化。大化。下述三個獨立的步驟是理解消費者行為的最佳方法:1. 消費者偏好2. 預(yù)算約束3. 消費者選擇5 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.consumer preferences3.

4、1market basketstable 3.1alternative market basketsa2030b1050d4020e3040g1020h1040market basketunits of foodunits of clothing6 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.some basic assumptions about preferences有關(guān)偏好的一些基本假設(shè)1. completeness: preferences are assumed to

5、 be complete. 完備性:偏好是完備的，note that these preferences ignore costs. 7 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.2. transitivity: preferences are transitive. 傳遞性:偏好是可傳遞的。3. more is better than less: goods are assumed to be desirablei.e., to be good. 越多越好8 of 40co

6、pyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.eag.indifference curves 無無差異曲線差異曲線 indifference curve curve representing all combinations of market baskets that provide a consumer with the same level of satisfaction.9 of 40copyright 2013 pearson education, inc. microeconomi

7、cs pindyck/rubinfeld, 8e.10 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.indifference maps無差異曲線簇?zé)o差異曲線簇 indifference map graph containing a set of indifference curves showing the market baskets among which a consumer is indifferent.11 of 40copyright 2013 pearson ed

8、ucation, inc. microeconomics pindyck/rubinfeld, 8e.indifference curves cannot intersectfigure 3.412 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.the shape of indifference curves13 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.the

9、 marginal rate of substitution邊際替代率(mrs) 為獲得一個單位的一種商品，必須放棄的另外一個商品的數(shù)量convexity 擬凸性擬凸性 when the mrs diminishes along an indifference curve, the curve is convex.14 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.perfect substitutes and perfect complements完全替代品與完全互補品完全替代

10、品與完全互補品完全替代品 當(dāng)一種商品對另一種商品的邊際替代率是常數(shù)時 ，兩種商品即為 完全替代品。 完全互補品 當(dāng)兩種商品的邊際曲線是直角形狀，他們的mrs為0或1，此時兩商品為完全互補商品。bad 厭惡品 少一點比多一點好的商品15 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.perfect substitutes and perfect complements16 of 40copyright 2013 pearson education, inc. microeconom

11、ics pindyck/rubinfeld, 8e.utility and utility functions效用和效用函數(shù)效用和效用函數(shù) utility numerical score representing the satisfaction that a consumer gets from a given market basket.效用 消費者從一個市場籃子中得到的滿足程度的數(shù)值表示。u (f,c ) =fc17 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.ordin

12、al versus cardinal utility序數(shù)效用和基數(shù)效用序數(shù)效用和基數(shù)效用 序數(shù)效用序數(shù)效用 能產(chǎn)生對市場籃子排序的效用函數(shù)被稱能產(chǎn)生對市場籃子排序的效用函數(shù)被稱為序數(shù)效用函數(shù)為序數(shù)效用函數(shù)。 基數(shù)效用基數(shù)效用 能描述一個市場籃子在多大程度上比另一個更受偏好的的效用函數(shù)。18 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.market baskets associated with the budget line f + 2c = $80 預(yù)算線 購買商品f和c的總

13、支出等于收入的情況下，所有的商品f和c的組合。budget constraints 預(yù)算約束預(yù)算約束3.2table 3.2market baskets and the budget linemarket basketfood (f)clothing (c)total spendinga 040$80b2030$80d4020$80e6010$80g80 0$80icpfpcf(3.1)19 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.(3.2)20 of 40copyrigh

14、t 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.the effects of changes in income and prices收入和價格變化的效應(yīng)21 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.價格變化的效應(yīng)價格變化的效應(yīng)figure 3.1222 of 40copyright 2013 pearson education, inc. microeconomics pindyck/

15、rubinfeld, 8e.consumer choice 消費者選擇消費者選擇3.3效用最大化的菜籃子必須滿足兩個條件:1. 它特必須位于預(yù)算線上.2. 他必須能給予消費者其最偏好的商品和服務(wù)的組合23 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.24 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e. marginal benefit 邊際效益 額外一單位商品的消

16、費所對應(yīng)的收益 marginal cost 邊際成本 額外一單位商品的消費所對應(yīng)的成邊際效益邊際效益=邊際成本邊際成本滿足程度最大化的點符合：mrs = pf/pc(3.3)25 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.角落點 在一個市場籃子中消費者的邊際替代率位不等于價格比的情況。 （ly: equality is allowed, not strict)figure 3.15corner solutions 角落點角落點26 of 40copyright 2013 pe

17、arson education, inc. microeconomics pindyck/rubinfeld, 8e.如果一位消費者選擇兩個菜籃子中的一個，那么消費者未必偏好那個被選中的菜籃子。（why? budget）如果一位消費者選擇兩個菜籃子中的一個，并且被選中的菜籃子比另一個更貴，那么消費者必定偏好那個被選中的市場籃子。revealed preference3.427 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e. marginal utility (mu) 邊際效用 對

18、從消費額外一單位的商品中所獲得的額外滿足的度量 diminishing marginal utility 邊際效用遞減 隨著一種商品的消費越來越多，額外的數(shù)量的消費所帶來的效用增加也越來越小。marginal utility and consumer choice邊際效用與消費者選擇邊際效用與消費者選擇3.528 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.邊際效用與消費者選擇3.5(/)mu/mucffc 0mu() mu ()fcfcmrs mu /mufcmrs/ppfc

19、mu/mu/ppffccmu/mu/ppffcc邊際相等原則邊際相等原則 是花在所有商品上的每一美元所帶來是花在所有商品上的每一美元所帶來的邊際效用相等。的邊際效用相等。ly: max u=u(x1,x2) st p1x1+p2x2=mthree ways to explain: math, figure and language29 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e. ideal cost-of-living index cost of attaining a gi

20、ven level of utility at current prices relative to the cost of attaining the same utility at base-year prices.理想生活成本指數(shù) 就是以當(dāng)前的價格達到一個給定效用水平所花成本相對于基期價格所達到相同效果所花成本的比值.cost-of-living indexes生活成本指數(shù)生活成本指數(shù)3.6 cost-of-living index ratio of the present cost of a typical bundle of consumer goods and services c

21、ompared with the cost during a base period.生活成本指數(shù) 指商品和服務(wù)的典型消費組合在當(dāng)期的成本與基期的成本之比30 of 40copyright 2013 pearson education, inc. microeconomics pindyck/rubinfeld, 8e.laspeyres index laspeyres price index amount of money at current year prices that an individual requires to purchase a bundle of goods and services chosen in a base year divided by the cost of purchasing the same bundle at base