经济学EconomicsforToday3E1备课讲稿课件.ppt

1、Chapter 1Introducing the economic way of thinking 3Key concepts Defining the economic problem Defining the three types of resources Understanding entrepreneurship What are macro and microeconomics?The purpose of modelling What is ceteris paribus?Defining positive and normative economics4The problem

2、of scarcity Scarcity forces us all to make choices as we never have the amount of goods and services we want:individuals:more clothes,etc.governments:more security,etc.Economics aims to explain what occurs as a result of scarcity because wants are forever greater than the available resources.6Resour

3、ces Resources are the basic categories of inputs used to produce goods and services.Resources are also called the factors of production and are split into three main categories:landlabourcapital.7Resources:land Any natural resource provided by nature used in the process of production,for example for

4、ests,minerals,wildlife,oil,rivers,lakes and oceans.May be renewable or non-renewable.8Resources:labour The mental and physical capacity of workers to produce goods and services,for example:farmersnurseslawyers.9Entrepreneurship Entrepreneurship is a special type of labour:the creative ability of ind

5、ividuals to organise and manage the combination of resources to produce goods and services.10Resources:capital Capital relates to human-made goods that produce goods and services.Capital does not directly satisfy wants but is used to produce the goods and services desired,such as a factory that prod

6、uce televisions.Money is not included in the economic definition of capital as it is simply a measure of value placed on goods.11Economics:the study of scarcity and choice Economics is the study of how society chooses to allocate its scarce resources to the production of goods and services in order

7、to satisfy unlimited wants.12Two branches of economics Microeconomics is the branch of economics that studies decision-making by a single individual,household,firm,industry or level of government.Macroeconomics is the branch of economics that studies decision-making for the economy as a whole.13The

8、methodology of economicsEconomists(like other scientists)use scientific method.Scientific method is a step-by-step procedure for solving problems.1Identify the problem.2Develop a model.3Test the model.14The steps in the model-building process15More about models A model is a simplified view of realit

9、y.It sets out the relationship between variables;causes and effects.A model is valid when it enables economists to forecast or predict the results of various changes in variables.Example:petrol consumption Identifying the problemPetrol consumption has fallen.Why?Developing a modelSelect variables pr

10、ice of petrol,price of cars.Express them verbally,graphically or mathematically.Testing the modelGather data which tells us how well the model estimates or predicts relationships.1617Hazards of the economic way of thinking There are two potential problems to be aware of:the ceteris paribus assumptio

11、npossible confusion of association and causation.18Ceteris paribus Ceteris(pronounced keteris)paribus is a Latin phrase which means other things remaining unchanged.Economists use this method as it enables them to see how a change in one variable affects the overall outcome.Imagine:if all the variab

12、les change at the same time,how would we know which one caused the change?19Association vs.causation We cannot always assume that when one event follows another,the first caused the second.For example,assume exports from Indonesia rose last month.Two events might be associated:The hole in the ozone

13、layer grew last month.Currency movements reduced the cost to Australians of buying Indonesian goods.But are they both possible causes?20Why do economists disagree?Economists agree on many things.As in other professions,disagreements occur.One explanation for disagreements is the difference between p

14、ositive and normative economics.21Positive economics Positive economics is an analysis limited to statements that are verifiable.Positive statements are testable they can be proven true or false.ExamplesAirbags save lives.Smoking is harmful to your health.22Normative economics Normative economics is

15、 an analysis based on value judgements.Normative statements cannot be proven by facts to be true or false.They express opinions good,bad,ought to,should.Examples:Every teenager who wants a job should have one.The government should allocate more money to education.Appendix to Chapter 1Applying graphs

16、 to economics24Key concepts Why use graphs in economics?What is a direct relationship?What is an inverse relationship?What is an independent relationship between two variables?How do we measure the slope of a line?How do graphs show three-variable relationships?25Graphs in economics Graphs are one o

17、f the simplest ways to present,aid and help us to understand relationships and to see economic concepts at work.Graphs help economists to understand the relationships that exist between variables.You should learn to draw,describe and interpret them.26A direct relationship A direct relationship is a

18、positive association between two variables.When one variable increases,the other also increases.When one variable decreases,the other also decreases.Note the line on the next slide has a positive slope.27A direct relationship28An inverse relationship An inverse relationship is a negative association

19、 between two variables.When one variable increases,the other decreases.When one variable decreases,the other increases.Note the line on the next slide has a negative slope.29An inverse relationship30An independent relationship An independent relationship is a zero association between two variables.W

20、hen one variable changes,the other remains unchanged.31An independent relationship32The slope of a straight line The ratio of change in the variable on the vertical axis(the rise or fall)to change in the variable on the horizontal axis(the run).Slope=rise/run=vertical axis/horizontal axis=Y/X33The s

21、lope of a curve A straight-line relationship is a linear relationship.The slope of a curve changes from one point on the curve to another.To determine the slope of a curve at any point,draw a tangent to the line at that point,and measure the slope of the tangent.34The slope of a curve35Introducing a

22、 third variable How can a model drawn in two dimensions show the impact of changes in a third variable?We must distinguish between movements and shifts.Movements along a graph show changes in one of the variables on the graphs axes.Shifts show changes in other variables.36A three-variable relationship