1.1 DEFINITIONS AND QUESTIONS
All economic questions and problems arise because human wants exceed the resources available to satisfy them.
Scarcity（稀缺性）
1.1 DEFINITIONS AND QUESTIONS
Microeconomic Questions
What? What goods and services get produced and in what quantities? How? How are goods and services produced? For Whom? For whom are the various goods and services produced?
The condition that arises because the available resources are insufficient to satisfy unlimited wants. Faced with scarcity, we must make choices—we must choose among the available alternatives. The choices we make depend on the incentives we face.
1.1 DEFINITIONS AND QUESTIONS
Incentive-(激励) An incentive is a reward or a penalty—a “carrot” or a “stick”—that encourages or discourages an action. （胡萝卜加大棒） Economics The social science that studies the choices that we make as we cope with scarcity and the incentives that influence and reconcile（使符合） our choices.
Checkpoint 1.1
5. Sort the following issues into microeconomics and macroeconomics. a. People must install catalytic（催化的） convert in their cars. b. U. S. unemployment should be much lower. c. Your local country opens a neighborhood gym（体育馆 gymnasium ） for teenager. 6. Match the following headlines with the What, How, and For whom questions. a. With more researches, we will cure cancer.（how） b. A good education is the right of every child.（whom） c. What will the government do with its budget surplus?（what）
1.2 ECONOMICS: A SOCIAL SCIENCE
Testing
A model’s predictions might correspond to or conflict with the data. Economic theory A generalization(一般规则) that summarizes what we understand about the economic choices that people make and the economic performance（绩效） of industries and nations.（个人-产业-国家）
1.2 ECONOMICS: A SOCIAL SCIENCE
The task can be broken into three steps: • Observing and measuring • Model building • Testing Observing and Measuring Items such as: • Quantities of resources • Wages and work hours • Prices and quantities of goods and services • Taxes and government spending • Volume of international trade
1.2 ECONOMICS:conomists is to discover how the economic world works. Economists distinguish between:
• Positive statements（实证经济学）: What is • Normative statements（规范经济学）: What ought to be The task of economic science:
Checkpoint 1.2
1. Concept explaining (1) economic model (2) economic theory (3) positive economics (4) normative economics
2. Classify each of the following statements as positive or normative a. There is too much poverty in the U.S. b. An increase in the gas tax will cut pollution c. Cuts to social Education in China have been too deep
1.2 ECONOMICS: A SOCIAL SCIENCE
Model Building
Economic model
A description of some aspect of the economic world that includes only those features of the world that are needed for the purpose at hand. （与目的相称 ） --简化，抽象，抓主要因素或主 要矛盾。（中医和西医-过程分析）
To discover and catalog positive statements that are consistent with what we observe in the world and that enable us to understand how the economic world works.
Margin：A choice that is made by comparing all the relevant alternatives systematically and incrementally（渐进地） .
1.3 THE ECONOMIC WAY OF THINKING
Marginal Cost
1.3 THE ECONOMIC WAY OF THINKING
Benefit: The gain or pleasure that
something brings. Benefit ：Gain Measured by What You Are
Willing to Give Up
On the Margin
Rational Choice
Using the available resources to satisfy most effectively the wants of the person making the choice. Cost: What You Must Give Up Opportunity cost The highest-valued alternative forgone(forgo 摒绝, 放弃; 对...断念; 谢绝 ).
Checkpoint 1.1
1. Give the definition of following statement (1) Scarcity (2) Incentive (3) Economics (4) Microeconomics (5) Macroeconomics 2. Economists studies choice that arise from one fact. What is the fact ? 3. Provide 3 examples of wants in China today that are especially pressing but not satisfied. 4. Provide an examples of an incentive that is like a carrot and one that like a stick.（tax or subsidy ）
1.经济模型（Economic Model）
描述经济事物的有关经济变量之间相互关系的理 论结构。
以供求为例：抽象出供给量、需求量、价格，用 数学表达式概括其关系： Qd = α－β（P） QS = －δ + γ（P） 一般地，模型方程数目应与所包含的未知数数目 相等，满足有解的要求。 Qd=Q S P=P
The cost of a one-unit increase in an activity Dirnk Coffee Marginal Benefit
What you gain when you get one more unit of something. Making a Rational Choice When we take those actions for which marginal benefit exceeds or equals marginal cost.