一、K元线性回归模型与一元线性回归模型的区别 二、关于模型的基本假设 三、k元线性回归模型的估计、检验和应用 四、理解OLSE的优良性质 五、比较OLS法与ML法的异同和适用性 六、如何综合评价经济计量建模的效果

• 一、多重共线性的概念 • 二、实际经济问题中的多重共线性 • 三、多重共线性的后果 • 四、多重共线性的检验 • 五、克服多重共线性的方法 • 六、案例 • *七、分部回归与多重共线性

布鲁金斯学会主席,美前总统经济顾问委员会主 席奥肯(Arthur Okun)根据美国1947-1960年 的数据,得到如下回归方程,称之为奥肯定律 y

Dummy variables a dummy variable is a variable that takes on the value l or o Examples: male(= 1 if are male, O otherwise), south(=l if in the south, 0 otherwise), etc dummy variables are also called binar variables. for obvious reasons Economics 20- Prof anderson

What is Heteroskedasticity Recall the assumption of homoskedastic implied that conditional on the explanator variables the variance of the unobserved error u was constant If this is not true that is if the variance of u is different for different values of thex's. then the errors are heteroskedastic

一、多元线性回归模型 二、多元线性回归模型的参数估计 三、OLS估计量的统计性质 四、参数估计量的方差-协方差矩阵和随机误差项σ2方差的估计 五、样本容量问题 六、多元线性回归模型实例

Time series vs Cross sectional e Time series data has a temporal ordering unlike cross-section data Will need to alter some of our assumptions to take into account that we no longer have a random sample of individuals Instead. we have one realization of a stochastic(i.e. random) process Economics 20- Prof anderson

Testing for AR(IS eria Correlation Want to be able to test for whether the errors are serially correlated or not Want to test the null thatp=0 in u,=pu, 1 +et=2.. where u is the model error

Fixed Effects estimation When there is an observed fixed effect. an alternative to first differences is fixed effects estimation Consider the average over time of y Bx1+…+Bxik+a1+l The average of a, will be ai so if you subtract the mean. a will be differenced out just as when doing first differences Economics 20- Prof anderson

Why Use Instrumental Variables? e Instrumental Variables(IV)estimation is used when your model has endogenous xs That is, whenever Cov(x,l)≠0 Thus. i can be used to address the problem of omitted variable bias 2 Additionally iv can be used to solve the classic errors-in-variables problem Economics 20- Prof anderson