计量经济学复习：chaptert1_The Nature of Econometrics and Economic Data

• What is ecometrics ?

　　Ecometrics is the use of statistical method to analysis economic data.Typically analyze nonexperimental data.

Nonexperimental data (observational data / retrospective data) are not accumulated through controlled experiments 

Experimental data are often collected in laboratory environments in the natural sciences, 

• Typical goals of econometric analysis:

1. Estimating relationship between economic variables 
2. Testing economic theories and hypotheses
3. Evaluating and implementing government and business policy

• Different kinds of economic data set:
  • Cross-sectional data: ignore any minor timing differences in collecting the data. (within one year)
    • Violation of random sampling: reveal/ size　　
  • Time series data 
  • Pooled cross section: different samples
  • Panel/Longitudinal data: the same cross-sectional units over a given time
• Causuality, Ceteris Paribus, and Counterfactual Reasoning