lectures.There are also some class discussions about related topics and cases Chapter 2 TOOLS OF POSITIVE ANALYSIS a.Obiectives and requirements 1)Understand the main role of economic theory 2)Master three main research methods 3)Be familiar with the conditions to prove causalities b.Content Section 1 The Role of Theory 1)Main Content a)The guidance of economic theory to action b)Causation versus correlation 2)Basic concepts and key points a)Basic concepts:substitution effect:income effect;causation;correlation: treatment group;control group. b)Key points:The role of a theory as a guiding framework;Three conditions of proving causality 3)Questions and application How to analyze the influence of income tax on the length of working hours according to the theory? Section 2 Experimental Studies 1)Main Content a)The characteristics of experimental research; b)Implementation and pitfalls of experimental research 2)Basic concepts and key points a)Basic concepts:cross section data,time series data;counterfactual situation,counterfactual condition. 3)Questions and application Section 3 Observational Studies 1)Main Content a)The connotation and scope of observational research 2)Basic concepts and key points lectures. There are also some class discussions about related topics and cases. Chapter 2 TOOLS OF POSITIVE ANALYSIS a. Objectives and requirements 1) Understand the main role of economic theory 2) Master three main research methods 3) Be familiar with the conditions to prove causalities b.Content Section 1 The Role of Theory 1) Main Content a) The guidance of economic theory to action b) Causation versus correlation 2) Basic concepts and key points a) Basic concepts: substitution effect; income effect; causation; correlation; treatment group; control group. b) Key points: The role of a theory as a guiding framework; Three conditions of proving causality 3) Questions and application How to analyze the influence of income tax on the length of working hours according to the theory? Section 2 Experimental Studies 1) Main Content a) The characteristics of experimental research; b) Implementation and pitfalls of experimental research 2) Basic concepts and key points a)Basic concepts: cross section data, time series data; counterfactual situation, counterfactual condition. 3) Questions and application Section 3 Observational Studies 1) Main Content a)The connotation and scope of observational research 2) Basic concepts and key points