2.1 1、Statistical or random experiment 2、Sample space or population Sample point, event 2.2 Stochastic or random variable (r. v.) 2.3 Probability 2.4 R.V. and probability density function
1. Recall the assumption for the CMLRM: (Homoskedasticity) 2. Counterexamples 1、rich family and poor family expenditures; 2、large company and small company sales. There exists heteroskedasticity in lots of econometric problems
2.1 Conditional Probability Distribution 2.2 Conditional Mean and Regression Analysis 2.3 Linear Regression Modelling 2.4 Correct Model Specification for Conditional Mean 2.5 Conclusion